obˈligate /-li-gāt/ transitive verb

1. To bind by contract or duty
2. To bind by gratitude
3. To constrain (US and archaic)

By necessity, without option

obligation /ob-li-gāˈshən/ noun

1. The act of obliging
2. A moral or legal bond, tie, or binding power
3. An action, promise or requirement of such a kind that failure to perform or fulfil it contravenes the law
4. The thing to which one is bound
5. A debt of gratitude
6. A favour
7. A bond containing a penalty in case of failure (law)

obligāˈtional adjective

obˈligātor noun

obligatorily /o-bligˈə-tər-i-li, ə-bligˈ or obˈlig-/ adverb

obligˈatoriness (or /obˈlig-/) noun

obligˈatory (or /obˈlig-/) adjective

1. Binding
2. Imposing duty
3. Imposed as an obligation
4. Obligate

obligee /ob-li-jēˈ/ noun

1. The person to whom another is bound by obligation (law)
2. Someone who is under an obligation for a favour

obligeˈment noun

A favour conferred

oblīgˈer noun

oblīgˈing adjective

1. Prepared to confer favours
2. Ready to do a good turn
3. Courteous

oblīgˈingly adverb

oblīgˈingness noun

obligor /obˈli-gör/ noun (law)

The person who binds himself or herself to another

obligate parasite noun (biology)

One capable of living naturally only as a parasite (cf facultative parasite)

holy day of obligation

(esp in the Roman Catholic Church) an important religious festival, on which attendance in church is obligatory