#1 flesh out v. make fat or plump; "We will plump out that poor starving child". wn #2 flesh out v. add details, as to an account or idea; clarify the meaning of and discourse in a learned way, usually in writing; "She elaborated on the main ideas in her dissertation". wn #3 flesh out v. become round, plump, or shapely; "The young woman is fleshing out". wn