helmet hair

1 7.4

Hair becomes flat and messy after wearing a helmet

noun
/ˈhɛlmɪt hɛr/

: pelo de casco

And I couldn't come to work with this matted down, sweaty old helmet hair.

Examples

I have helmet hair.

Shrek (2001)
After wearing his helmet all day, he complained about having helmet hair when he took it off.
She avoided wearing her helmet for too long, knowing it would give her helmet hair afterwards.
He laughed at his helmet hair in the mirror, realizing it was a common side effect of biking.

Surface Forms

helmet hair singular

helmet hairs plural

Morphology

helmet + hair

The meaning 'hair flattened or misshapen from wearing a helmet' is directly and transparently derived from combining 'helmet' (protective head covering) with 'hair' (head hair). This is a straightforward descriptive noun-noun compound with no idiomatic shift, so a B1 learner who knows the constituents would readily infer the meaning.

Etymology

Helmet hair comes from the simple picture of hair pressed and squashed by a tight helmet, leaving the hair flat or messy when you take it off. So, 'helmet hair' means hair that is 'flattened' or 'messy' after wearing a helmet.