Yarn spun about foremost of golfers up in arms (5)
I believe the answer is:
angry
'up in arms' is the definition.
(thesaurus)
'yarn spun about foremost of golfers' is the wordplay.
'spun' indicates an anagram.
'about' means one lot of letters goes inside another.
'foremost of' says to take the initial letters.
The first letter of 'golfers' is 'g'.
'yarn' with letters rearranged gives 'anry'.
'anry' placed around 'g' is 'ANGRY'.
(Other definitions for angry that I've seen before include "In a temper" , "Inflamed" , "Vexed" , "Upset" , "Irate, mad" .)