obligate

adj 1: (biology) restricted to a particular condition of life; "an

obligate anaerobe can survive only in the absence of

OXYGen" [ant: {facultative}]

2: being under moral or legal obligation; "felt bound by his

promise" [syn: {bound}, {compelled(p)}, {constrained(p)}]

v : force or compel somebody to do something; "We compel all

students to fill out this form" [syn: {compel}, {oblige}]