serious as a heart attack
In real, traceable use. Part of the curated seed collection; community review is coming.
Meaning · English
Completely serious and not joking at all.
Register: informal
Where it’s used:
Used
American English
Sources & notes
Adapted from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30 via kaikki.org).
Common questions
What does “serious as a heart attack” mean?
Completely serious and not joking at all.
Is “serious as a heart attack” formal or informal?
serious as a heart attack is generally informal.