expression
probably good; fine, isn't it?; very well
Dated or dialectal (especially Kyoto-ben) volitional/presumptive form of よい, equivalent to modern よいだろう. Used to express conjecture ('it's probably good') or to seek agreement ('it's fine, isn't it?'). Also used as an accepting response ('very well').
「これでよかろうか。」「ああ、よかろう。」
"Will this do?" "Yes, that'll be fine."
京都では「よろしおすなあ」と同じように「よかろう」と言うことがある。
In Kyoto, people sometimes say よかろう in the same way as よろしおすなあ.
Modern standard equivalent of よかろう. よかろう is dated or dialectal, while よいだろう is the contemporary volitional/presumptive form of よい.
Volitional/presumptive form of classical adjective よし (modern よい), formed with the auxiliary う. The form よかろう is a contraction of よくあろう, reflecting older morphological patterns.