like water off a duck's back

Idioms  

1. Readily and without apparent effect. For example, The scathing reviews rolled off him like water off a duck's back. This expression alludes to the fact that duck feathers shed water. [Early 1800s]

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Example Sentences

Now in its 19th series, criticism of The Apprentice falls "like water off a duck's back" these days, he said.

From BBC

"It's like water off a duck's back really, the way he just sort of takes it all in his stride," sports psychologist and former women's world number one darts player Dr Linda Duffy told BBC Sport.

From BBC

My club lose so often now though that a defeat is like water off a duck's back whatever the time and/or day.

From BBC

The Kordas realise the interest in their family but you sense it's like water off a duck's back.

From BBC

Merkel, however, took Trump's bloviations in stride — "like water off a duck's back" — pushing back with calm observations of fact.

From Salon