unreputable

adjective

1. held in good repute; honorable; respectable; estimable: a reputable organization.
2. considered to be good or acceptable usage; standard: reputable speech.

adjective

1. having a good reputation; honoured, trustworthy, or respectable
2. (of words) acceptable as good usage; standard

adj.1610s, from repute + -able. Meaning “having a good reputation” is from 1670s. Related: Reputably.