恐らく

Etymology
Abbreviation of, itself a contraction of obsolete , composed of +  +. Compare English use of the term, as in the phrases “I'm afraid so”, or “I'm afraid that ...”, to express a sense of.

Adverb

 * 1) probably, in all likelihood

Usage notes

 * Usually written in hiragana.
 * The term osoraku expresses a higher degree of certainty than tabun.
 * Often used when predicting a negative outcome.

Synonyms

 * : literally “eight or nine times out of ten”: in all likelihood
 * : maybe, perhaps, probably