Winter transport Santa primarily has guided (4)
I believe the answer is:
sled
'winter transport' is the definition.
(I've seen this before)
'santa primarily has guided' is the wordplay.
'primarily' indicates taking the first letters.
'has' means one lot of letters go next to another.
'guided' becomes 'led' ('lead' can be a synonym of 'guide').
The initial letter of 'santa' is 's'.
's'+'led'='SLED'
(Other definitions for sled that I've seen before include "Winter transport" , "Vehicle on runners" , "Snow transport" , "Snow vehicle" , "Toboggan (mainly US)" .)