na-adjective, noun
apathetic; lackadaisical; indolent; listless; weak-willed
Describes a person's temperament or attitude as lacking energy, motivation, or willpower. Formal/literary register.
彼の惰弱な態度には本当に失望した。
I was truly disappointed by his apathetic attitude.
暑さのせいで、一日中惰弱に過ごしてしまった。
Because of the heat, I spent the whole day listlessly.
na-adjective, noun
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.
病み上がりで体が惰弱になっている。
My body has become weak after recovering from illness.
その貴族は惰弱な若
The nobleman is portrayed as an effete young man.
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.