be off-colour

(British & Australian) also be off-color (American & Australian)

to not be feeling as well as usual He had flu a couple of months ago and he's been a bit off-colour ever since.

Name	Pronounced	Usage
FinnÉN	-	Irish
Odetta	-	English (Rare)
Shirlee	SHUR-lee	English
Emilija	EM-ee-lee-yah (Serbian, Croatian)	Lithuanian, Slovene, Serbian, Croatian, Macedonian
Livia (1)	LEE-vyah (Italian)	Italian, Romanian, Ancient Roman
Yuuko	yoo:-ko	Japanese