hold onto your hat

Phrase

humorous idiomatic usually

(idiomatic, usually humorous) Prepare for a shock! / Used other than figuratively or idiomatically: see hold, onto, hat.

Japanese Meaning

（冗談混じりに）これから驚くような出来事が起こるので、準備しておけ！ / （衝撃的な事態に備えて）覚悟を決めろ、しっかりと備えておけ

When I tell you the total bill, hold onto your hat — it's three times what we expected!

請求額を聞いたら覚悟してね。予想の三倍だったよ！

Sense（1）

(idiomatic, usually humorous) Prepare for a shock!

Hold onto your hat—intersecting planes are planes that cross, or intersect.

Sense（2）

Used other than figuratively or idiomatically: see hold, onto, hat.