Cover Westlife's first hit (4)
I believe the answer is:
wrap
'cover' is the definition.
(wrapping is a kind of covering)
'westlife's first hit' is the wordplay.
'first' indicates taking the first letters.
'hit' becomes 'rap' (I've seen this in other clues).
The initial letter of 'westlife' is 'w'.
'w'+'rap'='WRAP'
(Other definitions for wrap that I've seen before include "Enclose completely" , "Pack in paper; shawl" , "Enclose in paper or material" , "Flatbread snack" , "Swathe" .)