What does bilious mean?
Bilious is an adjective with two main uses. Literally, it refers to an excess of bile — the digestive fluid produced by the liver — and to the nausea and indigestion that were once blamed on it. Figuratively, and far more commonly today, it describes a person or mood that is irritable, cross, or bad-tempered: a bilious critic, for instance, is one whose reviews are sour and hostile. The word can also describe a sickly yellowish-green color reminiscent of bile itself, often applied to unflattering paintwork or lighting. Bilious entered English in the early seventeenth century from Latin bilis, meaning bile, and its figurative use preserves a trace of the ancient humoral theory that held human temperament to be governed by four bodily fluids. Though somewhat formal, it remains a vivid and expressive choice for describing ill humor.
adjectiveAffected by or suffering from an excess of bile, especially as formerly thought to cause irritability or indigestion; more broadly, irritable, bad-tempered, or peevish. It can also describe something having the yellowish-green color of bile.
- Suffering from, or as if from, an excess of bile; characterized by nausea or indigestion.
- Irritable, cross, or bad-tempered, as though affected by such a condition.
- Having the yellowish-green color of bile.
"After a sleepless night, he woke in a thoroughly bilious mood, snapping at everyone who crossed his path."
"She gave him a bilious glance and turned back to her newspaper without a word."
"The old wallpaper had faded to a distinctly bilious shade of green that no one could bear to look at."
Bilious comes from the ancient idea that too much yellow bile in your body literally made you grumpy — a theory doctors believed for over two thousand years.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of bilious
Bilious derives from the Latin noun bilis, meaning bile, the yellowish-green fluid secreted by the liver. The adjective entered English in the early seventeenth century, when medical thought still followed the ancient humoral theory that health and temperament depended on the balance of four bodily fluids. Under this doctrine, an excess of yellow bile was believed to produce both physical illness and an angry, irritable disposition, which is how bilious came to mean bad-tempered as well as sick. Cognates include choleric, from Greek chole, another classical word for bile that carried the same association with anger.
Related word forms
How bilious is actually used
Bilious sits on the formal end of the register — common in literary and editorial prose rather than casual conversation. Its figurative sense (irritable or sour-tempered) is by far the most frequent today; the literal medical sense reflects outdated humoral medicine and survives mainly in historical or clinical contexts. The word carries a mildly comic or contemptuous connotation when applied to a person's mood.
Easily confused with bilious
Billion is a number (a thousand million), while bilious describes irritability, ill humor, or a sickly yellowish color.