(adv) with considerable certainty; without much doubt, Syn. belike, in all probability, likely, in all likelihood, Example:He is probably out of the country; in all likelihood we are headed for war
The Collaborative International Dictionary of English (GCIDE) v.0.53 Collaborative International Dictionary (GCIDE)
[mashou ; masho (ik); mahyo (ik)] (exp) (1) (pol) (ましょ is a colloquialism in standard Japanese; まひょ is a colloquialism in Kansai dialect) (See ます) (used to express the speaker's volition) I'll; (2) (used to make an invitation, request, etc.) let's; (3) (See でしょう) (used to express a conjecture) probably