Meaning:
a horizon 
n.
the top layer of a soil profile; usually contains humus
hor Idiom, Proverb
a brick short
(See one brick short of a full load)
a few bricks short of a full load
not sensible or logical, not all there When Moe began eating bugs, we knew he was a few bricks short.
a horse of a different color
a different matter, a separate issue If he wants to buy the land, that's a horse of a different color.
a horse's ass
a fool, a jerk After three drinks he was acting like a horse's ass.
a short one
a small drink, a small amount of liquor """Can I pour you a drink?"" ""Yes. A short one, please."""
a thorn in my side
one who causes pain, one who bugs me He's always been a thorn in my side - always critical of me.
an old warhorse
a veteran, an old soldier, a classic story or tune The band played marches and overtures - the old warhorses.
anchor you
make you feel stable or confident When you have a crisis, your faith will anchor you.
beat a dead horse
continue to ask or try when there is no hope They won't refund your money. You're beating a dead horse.
bet on the wrong horse
base one
bring you up short
cause you to stop and think, rebuke you When I began to criticize Jan, Mother brought me up short.
cart before the horse
(See the cart before the horse)
caught short
not have enough money when you need it I was caught short and had to borrow some money from my father last week.
change horses in mid stream
change plans/methods after you have begun a competition or business We're in the furniture business, not clothing. We can't change horses in mid stream.
change horses in midstream
make new plans or choose a new leader in the middle of an important activity They have decided to change lawyers but I told them that they shouldn
dark horse
the competitor that could surprise us and win The dark horse in the World Cup is Ireland. They could win it all.
don't look a gift horse in the mouth
do not be critical of a gift, be grateful for a gift Don't evaluate a gift. Don't look a gift horse in the mouth.
eat like a horse
eat a lot, pig out Barney eats like a horse. He has a monstrous appetite.
expand your horizons
experience or discover new ideas or goals or cultures Travel, read, discuss - expand your horizons!
fall short
not able to do as well as planned I'm falling short of my career goals because I've been ill.
fall short (of one
not be as good as you expected, not succeed The new movie fell short of everyone
from the horse's mouth
(See straight from the horse's mouth)
get off your high horse
do not act like you are better than everyone else Colin acts so superior! Tell him to get off his high horse.
get on your horse
move, get started, get a move on Get on your horse or you'll be late for work. It's nearly 8!
hold your horses
wait a minute, hold on, hold the phone "When I said the accident was his fault, he said, ""Hold your horses!"""
hork
vomit, puke, barf, throw up Somebody horked on the floor of my car! Yuk!
horn in
interfere, intrude, butt in We were playing a game of tag, and the big guys tried to horn in.
horn in on
come in without an invitation or welcome, interfere He horned in on our conversation although he knows that nobody likes him.
horny
ready for sex, wanting to have sex, aroused How come you're never horny when I am?
horse around
play, joke, fool around, goof off Don't horse around in the lab. You could spill some acid.
horse feathers
lies, false stories, bull, a bunch of malarkey "When she told her dad she saw a ghost, he said, ""Horse feathers!"""
horse of a different color
(See a horse of a different color)
horse's ass
(See a horse's ass)
horse sense
wisdom in making decisions He doesn
horse shoes up his ass
very lucky, always winning He's got horseshoes up his ass! He won six games of bingo!
horse trade
a business agreement or bargain arrived at after hard bargaining After several hours of horse trading we finally reached an agreement to buy the new computers.
horseplay
just having fun, fooling around Don't worry. The boys aren't fighting. It's just horseplay.
in short supply
not enough, in less than the amount or number needed Experienced computer programmers are in short supply at our company.
line of authority
people in order of power, chain of command The line of authority goes from our manager up to the president.
lock the barn door after the horse is gone
be careful or try to make something certain after it is too late Now he wants to try and fix his house but it is like locking the barn door after the horse is gone. There was already a flood and the damage is done.
lock the barn door after the horse is stolen
be careful or try to make something safe when it is too late If you try and prevent a flood after the rains have started it is like locking the barn door after the horse is stolen.
long and the short of it
(See the long and the short of it)
look a gift horse in the mouth
complain if a gift is not perfect He shouldn
look up a dead horse's ass
do a worthless task, do a pointless exercise, pissing into the wind If they want a tax-free society, they may as well be looking up a dead horse's ass!
mad as a hornet
very angry, in a fighting mood He was as mad as a hornet when he came to work this morning.
make short work of something
finish quickly He made short work of the typing and has started working on the other documents.
off your high horse
(See get off your high horse)
on short notice
without much warning, at a moment's notice Can you come to work on short notice? Within a day or two?
one brick short of a full load
mentally slow, not all there I'm okay, but you may be one brick short of a full load. Ha ha.
piss like a race horse
have to urinate, back teeth are floating I hope this mall has a washroom. I have to piss like a race horse.