adj.形容詞無效的The check is invalid because it is not signed
n. (c./u.)名詞 (可數/不可數)生病的人Florence took care of the invalid at home
adj.形容詞無效的This is an invalid address.
n. (c./u.)名詞 (可數/不可數)無效物The system rejected the input as an invalid.
adj.形容詞不合邏輯的The argument presented was invalid due to a logical fallacy.
v.t.及物動詞因病退伍He was invalided out of the army after being wounded.
v.t.及物動詞使成為病人The war invalided many young men.