obligate

[v. ob-li-geyt; adj. ob-li-git, -geyt] /v. ˈɒb lɪˌgeɪt; adj. ˈɒb lɪ gɪt, -ˌgeɪt/
verb (used with object), obligated, obligating.
1.
to bind or oblige morally or legally:
to obligate oneself to purchase a building.
2.
to pledge, commit, or bind (funds, property, etc.) to meet an obligation.
adjective
3.
morally or legally bound; obliged; constrained.
4.
necessary; essential.
5.
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).
Origin
1400-50; late Middle English obligat (adj.) < Latin obligātus (past participle of obligāre to bind), equivalent to ob- ob- + ligātus; see ligate
Related forms
obligable
[ob-li-guh-buh l] /ˈɒb lɪ gə bəl/ (Show IPA), adjective
obligator, noun
nonobligated, adjective
preobligate, verb (used with object), preobligated, preobligating.
quasi-obligated, adjective
reobligate, verb (used with object), reobligated, reobligating.
unobligated, adjective
Can be confused
obligate, oblige.
British Dictionary definitions for obligating

obligate

/ˈɒblɪˌɡeɪt/
verb
1.
to compel, constrain, or oblige morally or legally
2.
(in the US) to bind (property, funds, etc) as security
adjective
3.
compelled, bound, or restricted
4.
(biology) able to exist under only one set of environmental conditions: an obligate parasite cannot live independently of its host Compare facultative (sense 4)
Derived Forms
obligable, adjective
obligative, adjective
obligator, noun
Word Origin
C16: from Latin obligāre to oblige
Word Origin and History for obligating

obligate

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.

obligating in Medicine

obligate ob·li·gate (ŏb'lĭ-gĭt, -gāt')
adj.
Able to exist or survive only in a particular environment or by assuming a particular role.

obligating in Science
obligate
  (ŏb'lĭ-gĭt, -gāt')   
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.