Wiktionary
a. (context idiomatic English) ill or unwell, especially as indicated by one's appearance. alt. (context idiomatic English) ill or unwell, especially as indicated by one's appearance.
Usage examples of "green about the gills".
Gus White, who had been sitting between Fazetti and Webber, went green about the gills, leapt to his feet and was sick in the corridor outside.
He was looking, I noticed, fairly green about the gills, and he conveyed the same suggestion of having just swallowed a bad oyster which I had observed in Kipper on his arrival at Brinkley.
When in conclusion he extracted an enormous eel from the horse's ear, followed by a mess of white porridge from the horse's brain, Matzerath himself was green about the gills but went right on with his act.
He was looking, Kilmara thought, distinctly green about the gills.
At its centre knelt Dan, somewhat green about the gills and red about the hooter.
CmEF O'BRIEN still felt a wee tad green about the gills, despite (or due to) having digested his fair share of an extract of the native plant life.
He didn't look exactly grief-stricken, although Astarth was a little green about the gills.
She was a pest and a pot of poison, of course, but all the same, he reflected charitably, it was a shame that she should look so green about the gills.
It seemed to Ty that the boy did look a little green about the gills, but that was no more than he felt himself.