Runner rejecting no-frills Nike trainers at last (3)
I believe the answer is:
ski
'runner' is the definition.
(something which 'runs', ie moves quickly on snow)
'rejecting no-frills nike trainers at last' is the wordplay.
'rejecting' shows that the letters should be reversed in order.
'no-frills' indicates the central letters (edge letters or 'frills' are removed).
'at last' says to take the final letters.
The central letters of 'nike' are 'ik'.
The last letter of 'trainers' is 's'.
'ik'+'s'='iks'
'iks' backwards is 'SKI'.
(Other definitions for ski that I've seen before include "Winter sports item" , "Snow-runner" , "Sport on piste" , "Hit the slopes" , "the end for many Russians" .)