Woman takes object to be of prime importance (5)
I believe the answer is:
vital
'be of prime importance' is the definition.
(I've seen this in another clue)
'woman takes object' is the wordplay.
'woman' becomes 'val' (val is a name for a woman).
'takes' means one lot of letters goes inside another.
'object' becomes 'it' (pronoun for an inanimate object).
'val' enclosing 'it' is 'VITAL'.
'to' is the link.
(Other definitions for vital that I've seen before include "Absolutely necessary or life-giving" , "Of the greatest importance" , "Imperative" , "Urgently needed or absolutely necessary" , "Critical; life-sustaining" .)