OBLIGATORILY

compulsorily, obligatorily, mandatorily

(adverb) in a manner that cannot be evaded; “the ministry considers that contributions to such a fund should be met from voluntary donations rather than from rates compulsorily levied.”

obligatorily

(adverb) in an obligatory manner; “this rule applies obligatorily”

Source: WordNet® 3.1

Etymology

Adverb

obligatorily (comparative more obligatorily, superlative most obligatorily)

In an obligatory manner.

Source: Wiktionary

Ob"li*ga*to*ri*ly, adv.

Definition: In an obligatory manner; by reason of obligation. Foxe.

OBLIGATORY

Ob"li*ga*to*ry, a. Etym: [L. obligatorius: cf.F. obligatoire.]

Definition: Binding in law or conscience; imposing duty or obligation; requiring performance or forbearance of some act; -- often followed by on or upon; as, obedience is obligatory on a soldier. As long as the law is obligatory, so long our obedience is due. Jer. Taylor.

Source: Webster’s Unabridged Dictionary 1913 Edition