Uplifting fragment of favourite yarn of The Abominable Snowman (4)
I believe the answer is:
yeti
'the abominable snowman' is the definition.
(I've seen this before)
'uplifting fragment of favourite yarn' is the wordplay.
'uplifting' shows that the letters should be reversed in order.
'fragment of' says the answer is hidden in the clue (I've seen this in other clues).
'itey' can be found hidden inside 'favourite yarn'.
'itey' back-to-front is 'YETI'.
'of' is the link.
(Other definitions for yeti that I've seen before include "hairy thing proving elusive" , "creature awaiting discovery?" , "Himalayan mystery" , "Highly elusive monster" , "Himalayan monster?" .)