Thin female, horribly slimy (6)
I believe the answer is:
Here is my best explanation:
'thin' is the definition.
('flimsy' can be similar in meaning to 'thin')
'female horribly slimy' is the subsidiary indication.
'female' becomes 'f' (abbreviation).
'horribly' is an anagram indicator.
'slimy' with letters rearranged gives 'limsy'.
(Other definitions for flimsy that I've seen before include "Light and thin, fragile", "Lacking strength and solidity", "Light and thin, easily torn or broken", "Light and thin, material or argument, perhaps", "Lightweight", "Fragile, of loose structure", "Weak, insubstantial", "Thin, insubstantial", "Of loose structure, fragile" and "Not strong".)