Slackens off when the trade union gets into some trouble (9)
I believe the answer is:
moderates
'slackens off when' is the definition.
I can't tell whether this defines the answer.
'trade union gets into some trouble' is the wordplay.
I cannot quite see how this works, but
an anagram of 'trade' is 'derat' which is within the answer.
an anagram of 'some' is 'moes' which is located in the left over letters.
No letters remain.
This explanation may well be incorrect...
'the' is the link.
Can you help me to learn more?
(Other definitions for moderates that I've seen before include "People who don't have extreme views, say about politics" , "chairs" .)