verb (used with object), ob·li·gat·ed, ob·li·gat·ing.
- to bind or oblige morally or legally: to obligate oneself to purchase a building.
- to pledge, commit, or bind (funds, property, etc.) to meet an obligation.
- morally or legally bound; obliged; constrained.
- necessary; essential.
- Biology. restricted to a particular condition of life, as certain organisms that can survive only in the absence of oxygen: obligate anaerobe (opposed to facultative).
- to compel, constrain, or oblige morally or legally
- (in the US) to bind (property, funds, etc) as security
- compelled, bound, or restricted
- biology able to exist under only one set of environmental conditionsan obligate parasite cannot live independently of its host Compare facultative (def. 4)
v.1540s, “to bind, connect;” 1660s, “to put under moral obligation,” back-formation from obligation, or else from Latin obligatus, past participle of obligare (see oblige). Oblige, with which it has been confused since late 17c., means “to do one a favor.” Related: Obligated; obligating. adj.
- Able to exist or survive only in a particular environment or by assuming a particular role.
- Capable of existing only in a particular environment or by assuming a particular role. An obligate aerobe, such as certain bacteria, can live only in the presence of oxygen. An obligate parasite cannot survive independently of its host. Compare facultative.