apathetic; lackadaisical; indolent; listless; weak-willed
Describes a person's temperament or attitude as lacking energy, motivation, or willpower. Formal/literary register.
weak; feeble; effeminate; enervated
Refers to physical or constitutional weakness, often with a nuance of lacking vigor or being unmanly. Formal/literary; 'effeminate' is a dated usage.
I was truly disappointed by his apathetic attitude.
Because of the heat, I spent the whole day listlessly.
My body has become weak after recovering from illness.
The nobleman is portrayed as an effete young man.
弱々しい is a common i-adjective for 'weak-looking' or 'feeble' in appearance or manner, while 惰弱 is a formal na-adjective/noun for inherent weakness or listlessness.
Standard kanji form for this formal/literary word.
Alternate kanji form; less common than 惰弱.
Compound of 惰 (lazy, idle) and 弱 (weak). The exact historical derivation is uncertain; the spelling is conventionally associated with the meaning of weakness and indolence.