Egg males to create sign (4)
I believe the answer is:
omen
'sign' is the definition.
(omen is a kind of sign)
'egg males' is the wordplay.
'egg' becomes 'o' (an 'o' resembles an egg).
'males' becomes 'men' (man is a kind of male).
'o'+'men'='OMEN'
'to create' acts as a link.
(Other definitions for omen that I've seen before include "writing on the wall" , "Forecast" , "Portent, prophetic sign" , "Augury, portent" , "premonition" .)