He was known for being two-faced, saying one thing and doing another.
multiple personalities
Frequency:
70
%
She was diagnosed with multiple personalities.
divided self
Frequency:
60
%
She struggled with her divided self, never feeling whole.
dual identity
Frequency:
45
%
His dual identity caused confusion among his friends.
Idiomatic Expressions for split personality
Phrase: show a split personality
Meaning: to display conflicting or inconsistent behavior
Usage: His actions show a split personality; he can be kind and generous one moment, then rude and selfish the next.