Disagreements in first form (5)
I believe the answer is:
rifts
'disagreements' is the definition.
(I've seen this in another clue)
'first form' is the wordplay.
'form' indicates an anagram (a different form of the same letters).
'first' with letters rearranged gives 'RIFTS'.
'in' is the link.
(Other definitions for rifts that I've seen before include "Schisms" , "Splits" , "differences ..." , "Breaks, severances" , "Clefts or fissures." .)