The term 'FULL OF BACK TALK' can be summarized by two crossword solutions: 'LIPPY' and 'SASSY'. Both words describe someone who is cheeky and disrespectful, often responding to authority with insolence. LIPPY is a British slang term for someone who is rude or impudent, while SASSY is an American slang term for someone who is bold and outspoken. Both terms imply that the person is not afraid to speak their mind, even if it means challenging authority.