1. [adv]  directly; "we must talk man-to-man"
2. [adj]  (sports) being a system of play in which an individual defensive player guards an individual offensive player; "one-on-one defense"
3. [adj]  forthright and honest; "had a man-to-man talk about the facts of life"

MAN-TO-MAN is a 10 letter word that starts with M.