OBLIGATION n. 2 definitions
That which obligates or constrains; the binding power of a promise, contract, oath, or vow, or of law; that which constitutes legal or moral duty. A tender conscience is a stronger obligation than a proson. Fuller.
OPPOSITE a. 2 definitions
Extremely different; inconsistent; contrary; repugnant; antagonistic. Novels, by which the reader is misled into another sort of pieasure opposite to that which is designed in an epic poem. Dryden. Particles of speech have divers, and sometimes almost opposite, significations. Locke.