Антонимом highly improbable

probable likely certain doubtless plausible reasonable ordinary ostensible possible probably real tenable positive assured confident sure clear sanguine

believable convincing realistic credible probable likely reasonable creditable persuasive possible conceivable smooth tenable glib imaginable acceptable sound logical smooth-talking feasible smooth-tongued authentic rational specious verisimilar cogent thinkable colourable trustworthy reliable presumptive fair-spoken able to hold water within the bounds of possibility with a ring of truth plausible supposable cogitable usual common sensible good normal ordinary strong familiar regular expected solid unquestionable fathomable probably compelling fair valid certain incontrovertible believeable aboveboard definite powerful sure anticipated well-founded bad poor describable customary commonplace possibly trusty real serious tiny comprehensible pragmatic true to life cheap conjecturable unromantic practical workable high odds-on unamazing simple plain inferior coherent satisfactory competent lucid satisfying conclusive incontestable adequate large massive to be expected on the cards promising foreseeable predicted influential dependable unassailable potent sane reasoned effective clear commonsense substantial well-grounded up front distinct decent concentrated sufficient full intelligent great

true factual real actual exact realistic accurate genuine unelaborated authentic nonfictional precise veracious case legitimate reliable undoubted unfaked valid veridical faithful literal undeniable unquestionable veristic veritable correct historical proper unpretentious verifiable convincing hard lifelike unerring unpretending unvarnished close documentary fact-based matter-of-fact objective verisimilar as it really happened bang on in accordance with reality on the mark on the money spot on spot-on telling it like it is true to life what actually happened what really happened credible plausible believable honest bona fide probable sincere trustworthy truthful sound indubitable legit likely dependable creditable persuasive unfeigned tenable aboveboard conceivable straight for real up front

clear-eyed clear-sighted cynical pragmatic practical realistic logical rational sensible businesslike reasonable utilitarian functional commonsensical unsentimental hard down-to-earth

high good increased massive big significant strong considerable enormous huge favourable extraordinary inordinate great fine sizable favorable tremendous excellent substantial large serious extreme sizeable likely major probable meaningful

likely probable expected prospective anticipated foreseeable destined predicted presumable fated predictable promising true odds-on distinctly possible to be expected

logical self-consistent self-evident

usual customary common typical ordinary average banal everyday familiar conventional expected normal regular standard commonplace general plain unnoteworthy generic hackneyed unexceptional unextraordinary unremarkable routine

applicable feasible functional operable operational practicable practical serviceable ultrapractical usable useable useful utilisable utilizable workable

unquestionable incontestable undeniable undisputable conclusive incontrovertible indubitable absolute categorical reliable convinced genuine unmistakable definite indisputable irrefragable undoubtable proven trustworthy unarguable unassailable certain flawless irrefutable authentic clear cold unambiguous unimpeachable veritable dependable faultless true unchallengeable decided likely undoubted inarguable probable real unequivocal beyond doubt beyond question bona fide well-founded well-grounded without doubt without a shred of doubt

known

achievable acquirable attainable feasible obtainable practicable practical reachable realistic realisable realizable accessible viable winnable accomplishable gettable possible reasonable conceivable conservative doable likely potential probable procurable

highly infectious highly infective high-lying highly leveraged highly priced highly-processed food highly-flavoured highly favourable highly-developed highly developed highly contagious highly complimentary