Source of iron for chaps in trouble (7)
I believe the answer is:
spinach
'source of iron' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'chaps in trouble' is the wordplay.
'trouble' indicates anagramming the letters.
'chaps'+'in'='chapsin'
'chapsin' with letters rearranged gives 'SPINACH'.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for spinach that I've seen before include "food" , "something to eat" , "Dark green vegetable" , "leaves on plate?" , "Blackboard stand" .)