conspicuous by your absence
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 absenceobviously 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.