Dangerous creatures in lingerie business, at first (6)
I believe the answer is:
cobras
'dangerous creatures' is the definition.
(type of snake)
'lingerie business at first' is the wordplay.
'lingerie' becomes 'bras' (item of underwear or lingerie).
'business' becomes 'co' (short for company).
'at first' is a charade indicator (letters next to each other).
'bras' after 'co' is 'COBRAS'.
'in' acts as a link.
(Other definitions for cobras that I've seen before include "Venomous creatures" , "Carobs for the reptiles" , "Hooded snakes" , "Slippery creatures" , "Highly venomous snakes" .)