Pole grabbing beastly female, life-saver (3,4)
I believe the answer is:
mae west
'life-saver' is the definition.
(Mae West is an informal name for a life jacket)
'pole grabbing beastly female' is the wordplay.
'pole' becomes 'mast' (mast is a kind of pole).
'grabbing' indicates putting letters inside.
'beastly female' becomes 'ewe' (female sheep).
'mast' enclosing 'ewe' is 'MAE WEST'.
(Other definitions for mae west that I've seen before include "I acted" , "Film star; WW2 jacket" , "Actress - life jacket" , "buoyant supporter" , "20th century film star (Diamond Lil)" .)