Lions' conceit (5)
I believe the answer is:
pride
I believe this clue is a double definition.
'lions'' is the first definition.
(pride is the collective noun for a group of lions)
'conceit' is the second definition.
(I've seen this before)
(Other definitions for pride that I've seen before include "Leonine family" , "Group of lions" , "Deadly sin (of lions?)" , "cause of swelling?" , "They say it comes before a fall" .)