noun
coward; wimp; weak-willed person
A derogatory term for someone lacking courage or resolve. Often used in informal or critical contexts.
彼は軟弱者だから、困難に立ち向かえない。
He's a coward, so he can't face difficulties.
そんな軟弱者にリーダーは務まらない。
A wimp like that can't be a leader.
弱虫 is a more colloquial and childish term for a weakling or crybaby, whereas 軟弱者 is more formal and critical.
Compound of 軟弱 (weak, spineless) and 者 (person). The exact historical derivation is uncertain, but the spelling is conventionally associated with the meaning.