Got up, rejecting small eggs (3)
I believe the answer is:
roe
'eggs' is the definition.
(I've seen this in other clues)
'got up rejecting small' is the wordplay.
'got up' becomes 'rose' (I've seen this before).
'rejecting' suggests deleting specific letters.
'small' becomes 's' (abbreviation - e.g. clothes size).
'rose' with 's' taken away is 'ROE'.
(Other definitions for roe that I've seen before include "Mass of fish eggs" , "A mass of fish-eggs" , "Hoofed animal(s)" , "Mass of fish's eggs" , "Fish eggs; small deer" .)