Early spring: keep in seaside resort (7)
I believe the answer is:
margate
'seaside resort' is the definition.
'margate' can be an answer for 'resort' (I have seen 'coastal resort' mean 'margate' so perhaps 'resort' could also mean 'margate'). I'm unsure of the 'seaside' bit.
'early spring keep in' is the wordplay.
'early spring' becomes 'Mar' (short for March).
'keep in' becomes 'gate' (gate can mean to confine a student to a college).
'mar'+'gate'='MARGATE'
Can you help me to learn more?
(Other definitions for margate that I've seen before include "N. Kent seaside resort" , "resort town" , "Kentish Town?" , "place in England" , "coastal resort" .)