Did favours when compelled? (7)

I believe the answer is:

obliged

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'compelled?' is the definition.
('oblige' can be a synonym of 'compel')

I don't understand how the rest of the clue works.

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(Other definitions for obliged that I've seen before include "Grateful - compelled" , "Morally or legally bound (to do something)" , "Compelled by duty" , "Did favour to, or coerced" , "Duty-bound" .)

I've seen this clue in The Globe and Mail.

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