1. hairshirt - Noun
2. hairshirt - Adjective
A shirt made of haircloth; especially one worn by ascetics or the penitent.
Synonyms: cilice, horsehair shirt, sackcloth
(figuratively) A state of penitence and humility.
hairshirt (not comparable)
(relational) Advocating or adopting a relatively ascetic lifestyle, especially for environmentalist reasons.