noun, na-adjective
Used adverbially as まともに to mean 'directly', 'head-on', or 'straight'. The noun use is less common.
See also: まともに
彼はまともに私の顔を見なかった。
He didn't look me straight in the face.
まともに風を受けて進む。
Advance straight into the wind.
na-adjective, noun
honest; decent; proper; serious; sensible
Describes a person, action, or thing that is upright, respectable, or not crooked. Often used in negative contexts to mean 'not decent' or 'not serious'.
まともな人間ならそんなことはしない。
A decent person wouldn't do such a thing.
彼の言うことはまともだ。
What he says is sensible.