a trump card

Meaning: A decisive advantage kept in reserve.

Language: English

Literally: (Already vivid in English)

Example: “Her knowledge of the local market was the trump card in the negotiation.”

Category: Daily Life

Origin: In card games, the trump suit beats all others; "trump" comes from "triumph." The figurative use is recorded from the 19th century.

Equivalents in other languages

hide one's light under a bushel — To keep one's talents hidden.
charity begins at home — One's first duty is to one's own family.
a load of nonsense — Something completely untrue or silly.
all or nothing — With no middle way; everything is risked on one outcome.
an accident waiting to happen — Someone or something very likely to cause trouble or harm.
on a wing and a prayer — Only just managing, with luck rather than means.

not turn a hair — To show no reaction at all.
all brawn and no brain — Physically strong but not clever.
two men and a dog — A very small crowd.
has the cat got your tongue? — Said to someone who stays silent when they should speak.
until one is blue in the face — For as long as one likes, with no result.
welcome to the club — Said to someone who has just joined you in a shared situation, usually an unwelcome one.

The sixth sick sheikh's sixth sheep's sick. — Believed by Guinness to be among the hardest in English — 'six/sick/sheikh/sheep' blur in…
Betty Botter bought some butter, but she said the butter's bitter. — A 'b / t / tt' plosive drill that bounces between Betty, butter, and bitter.
She sells seashells by the seashore. — The definitive 's' versus 'sh' alternation — the tongue has to switch place of articulati…