• КАК РЫБКЕ <РЫБЕ> ЗОНТИК нужен highly coll
[как + NP; these forms only; adv (neg intensif)]
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⇒ completely unnecessary, of no use to s.o.:
- (be as much use to s.o.) as an umbrella to a duck;
- (need sth.) like <as> a duck needs an umbrella.
Большой русско-английский фразеологический словарь. — М.: ACT-ПРЕСС КНИГА. С.И. Лубенская. 2004.