undertaking

noun

1 why did you get involved in such a risky undertaking?:

enterprise, venture, project, campaign, scheme, plan, operation, endeavour, effort, task, assignment, charge, activity, pursuit, exploit, job, business, affair, procedure, proceeding, process, transaction;

mission, quest, exploration, expedition.

2 all students shall sign an undertaking to comply with the regulations of the university:

pledge, agreement, promise, oath, covenant, vow, word, word of honour, solemn word, bond, commitment, guarantee, assurance, warrant, contract, compact.

undertaking (1) Oxford Dictionary of English