Tease a lord about an animal (4)
I believe the answer is:
seal
'an animal' is the definition.
(I have seen 'Marine animal' mean 'seal' so perhaps 'animal' could also mean 'seal')
'tease a lord about' is the wordplay.
'about' indicates the answer is hidden within the clue.
'SEAL' is hidden within 'tease a lord'.
(Other definitions for seal that I've seen before include "Secure against leakage" , "Sea-dweller can produce a wax impression" , "Ratify" , "Fasten securely; aquatic mammal" , "Amphibious fish-eating sea mammal" .)