Definition of flatters:
(v) :
To compliment someone, often (but not necessarily) insincerely and sometimes to win favour.
(v) :
To enhance or gratify someone's vanity by praising them.
(v) :
To portray someone to advantage.
(v) :
To encourage or cheer someone with (usually false) hope.
(v) :
(usually reflexive) To cheer or please (with the idea that); congratulate oneself, especially when the perception is false.
(n) :
Someone who flattens, purposely or accidentally. Also flattener.