BELIEVABLY
believably
(adverb) in a believable manner; “he acted believably sincere”
credibly, believably, plausibly, probably
(adverb) easy to believe on the basis of available evidence; “he talked plausibly before the committee”; “he will probably win the election”
Source: WordNet® 3.1
Etymology
Adverb
believably (comparative more believably, superlative most believably)
In a believable way.
Used to express the speaker's assessment of the credibility of a reported statement.
Antonyms
• unbelievably
Source: Wiktionary
BELIEVABLE
Be*liev"a*ble, a.
Definition: Capable of being believed; credible.
– Be*liev"a*ble*ness, n.
– Be*liev`a*bil"i*ty (, n.
Source: Webster’s Unabridged Dictionary 1913 Edition