Obligation - Crossword Clue, Answer and Explanation

'obligation' is the definition.
(I know that obligation can be written as duty)

This is all the clue.

(Other definitions for duty that I've seen before include "Levy - tax on imports" , "Service - tax - office" , "Not subject to customs tax" , "A tax; compulsory task" , "assignment" .)

I've seen this clue in The New York Times, the USA Today, the Penny Press, the Universal, The Telegraph, the King Feature Syndicate, the LA Times, The Washington Post, The Guardian, The Star Tribune, The Sun, the Sydney Morning Herald, The Independent, the Evening Standard, The Mirror and the Newsday.

'obligation' is the definition.
(I've seen this in another clue)

This is all the clue.

(Other definitions for onus that I've seen before include "'Responsibility, task or burden (4)'" , "Encumbrance" , "'Burden, load (4)'" , "Responsibilty" , "Liability" .)

I've seen this clue in The New York Times, the USA Today, the Penny Press, the Universal, The Telegraph, the King Feature Syndicate, the LA Times, The Washington Post, The Guardian, The Star Tribune, The Sun, the Sydney Morning Herald, The Independent, the Evening Standard, The Mirror and the Newsday.

'obligation' is the definition.
(I know that debt is a type of obligation)

This is all the clue.

(Other definitions for debt that I've seen before include "Money owed or due" , "Something owed" , "Arrears, liability" , "What's due" , "outstanding" .)

I've seen this clue in The New York Times, the USA Today, the Penny Press, the Universal, The Telegraph, the King Feature Syndicate, the LA Times, The Washington Post, The Guardian, The Star Tribune, The Sun, the Sydney Morning Herald, The Independent, the Evening Standard, The Mirror and the Newsday.

Obligation (4)