conspicuous by (one's) absence
Noticeably missing from something. You're the loudest one in the class, so of course you're conspicuous by your absence!
conspicuous by your absence
obviously not present in a place where you should be. This phrase was coined by Lord John Russell in a speech made in 1859 . He acknowledged as his source for the idea a passage in Tacitus describing a procession of images at a funeral: the fact that those of Cassius and Brutus were absent attracted a great deal of attention.
conˌspicuous by your ˈabsence
not present in a situation or place, when it is obvious that you should be there: When it came to cleaning up afterwards, Anne was conspicuous by her absence.