Contractors on island wearing brown stay dry (7)
I believe the answer is:
abstain
'stay dry' is the definition.
Although both the answer and definition are verbs in their base form, I don't see how they can define each other.
'contractors on island wearing brown' is the wordplay.
'contractors on' becomes 'abs' (I can't explain this - if you can you should give a lot more credence to this answer).
'island' becomes 'i' (geographical abbreviation).
'wearing' is an insertion indicator.
'brown' becomes 'tan' (tan is a kind of brown).
'i' inserted inside 'tan' is 'tain'.
'abs'+'tain'='ABSTAIN'
Can you help me to learn more?
(Other definitions for abstain that I've seen before include "Deny oneself" , "Pass" , "'Refrain from, voting or eating, say (7)'" , "Withhold one's vote" , "Stay neutral, in a way" .)