Knotty question, ultimately spreading load (5)
I believe the answer is:
nodal
'knotty' is the definition.
(thesaurus)
'question ultimately spreading load' is the wordplay.
'ultimately' suggests the final letters.
'spreading' indicates an anagram.
The final letter of 'question' is 'n'.
'load' is an anagram of 'odal'.
'n'+'odal'='NODAL'
(Other definitions for nodal that I've seen before include "Like swelling" , "Knotty" , "At a critical point" , "junction" , "Relating to network intersections" .)