Greens, at first boiled, mashed: many thanks! (7)
I believe the answer is:
obliged
'greens at first boiled mashed many thanks' is the definition.
I can't tell whether this defines the answer.
'greens at first boiled mashed' is the wordplay.
'at first' indicates taking the first letters.
'mashed' indicates anagramming the letters.
The first letter of 'greens' is 'g'.
'g'+'boiled'='gboiled'
'gboiled' is an anagram of 'OBLIGED'.
Can you help me to learn more?
(Other definitions for obliged that I've seen before include "Constrained" , "Did favours - compelled" , "required" , "Bound by a favour rendered" , "Duty-bound" .)