man-to-man

adjectives

forthright and honest
"had a man-to-man talk about the facts of life"
is similar to
straightforward in means or manner or behavior or language or action
"a direct question"; "a direct response"; "a direct approach"
being a system of play in which an individual defensive player guards an individual offensive player
"one-on-one defense"

adverbs

directly
"we must talk man-to-man"