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quack like a duck

vb. (context simile English) To appear to be exactly what one is.

Usage examples of "quack like a duck".

But as you crow like a rooster or quack like a duck or moo like a cow, scrutinize your brother or sister Discordian with alert interest - never cracking a smile - to see how he or she will respond.

Unless while you're under, I can convince the hypnotist to make you quack like a duck.

If you miss the ball, you have to get down on your knees and quack like a duck.