Irregular hours that are needed to negotiate (6,3)
I believe the answer is:
thrash out
'negotiate' is the definition.
The definition and answer can be both to do with communicating as well as being verbs in their base form.
Maybe they are linked in a way I don't understand?
'irregular hours that are needed' is the wordplay.
'irregular' is an anagram indicator.
'are needed' is a charade indicator (letters next to each other).
'hours'+'that'='hoursthat'
'hoursthat' anagrammed gives 'THRASH OUT'.
'to' acts as a link.
Can you help me to learn more?
(Another definition for thrash out that I've seen is " Debate".)