put it mildly

Understate, say without exaggeration, as in It's a fairly long way to walk, to put it mildly-twenty miles or so. [First half of 1900s]

Name	Pronounced	Usage
Aurelius	[ɔ:'ri:jəs]
Acland	['æklənd]
Annett	-	German
Diamantina	-	Greek
Habakkuk	HAB-ə-kək (English), hə-BAK-ək (English)	Biblical
BeÑAt	-	Basque