harden up
In real, traceable use. Part of the curated seed collection; community review is coming.
Sense 1
Meaning · English
To tighten up a sailboat's sheets in order to prevent luffing.
Sources & notes
Adapted from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30 via kaikki.org).
Sense 2
Meaning · English
To become or make (something, someone) hard, either literally or figuratively.
Register: informal
Sources & notes
Adapted from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30 via kaikki.org).
Common questions
What does “harden up” mean?
To tighten up a sailboat's sheets in order to prevent luffing.
Is “harden up” formal or informal?
No register label has been reviewed yet — treat it as neutral and check the usage notes above.