'Undesirable' definitions:

Definition of 'undesirable'

From: WordNet
adjective
Not wanted; "undesirable impurities in steel"; "legislation excluding undesirable aliens";"removed the unwanted vegetation" [syn: undesirable, unwanted] [ant: desirable]
adjective
Not worthy of being chosen (especially as a spouse) [syn: undesirable, unsuitable]
noun
One whose presence is undesirable; "rounding up vagrants and drunks and other undesirables"

Definition of 'Undesirable'

From: GCIDE