Another word for frank
candid, straightforward, sincere, open, forthright, outspoken, direct, honest, artless, free, easy, familiar, free in speaking, unreserved, undissembling, uninhibited, unguarded, downright, aboveboard, ingenuous, unsophisticated, unaffected, plain, apparent, open-faced, saying what one thinks, straight, plain-spoken, free-spoken, natural, guileless, blunt, bold, openhearted, matter-of-fact, explicit, straight from the shoulder*, flat-out*, straight-out*, calling a spade a spade*, upfront*.
frank applies to a person, remark, etc. that is free or blunt in expressing the truth or an opinion, unhampered by conventional reticence a frank criticism; candid implies a basic honesty that makes deceit or evasion impossible, sometimes to the embarrassment of the listener a candid opinion; open implies a lack of concealment and often connotes an ingenuous quality the open candor of a child; outspoken suggests a lack of restraint or reserve in speech, esp. when reticence might be preferable