What is Frank ?
Frank is (adj) saying what you think To be really frank with you I think the plan stinks. He gave her some frank advice. Synonym forthright. Antonym insincere (NOTE: Do not confuse with franc.) (verb) to stamp a letter with a special machine, instead of using a postage stamp The letters were all franked before they left the office.
source: Easier English, Student Dictionary Upper Intermediate Level