|Kanji in this term|
Abbreviation of 恐らくは (osoraku wa), itself a contraction of obsolete 恐るらくは (osoruraku wa), composed of 恐る (osoru, “to fear”, obsolete earlier form of modern 恐れる osoreru) + らく (-raku, “state, act, or fact of doing”, nominalizing suffix) + は (wa, topic particle). Compare English use of the term afraid, as in the phrases “I'm afraid so”, or “I'm afraid that ...”, to express a sense of probably.
- 十中八九 (jutchū hakku): literally “eight or nine times out of ten”: in all likelihood
- 多分 (tabun): maybe, perhaps, probably
The term osoraku expresses a higher degree of certainty than tabun.