All obligatory antonyms
o·blig·a·to·ry
O o adjective obligatory
- optional — left to one's choice; not required or mandatory: Formal dress is optional.
- free — enjoying personal rights or liberty, as a person who is not in slavery: a land of free people.
- unnecessary — not necessary or essential; needless; unessential.
- voluntary — done, made, brought about, undertaken, etc., of one's own accord or by free choice: a voluntary contribution.
- nonessential — not essential; not necessary: Nonessential use of gasoline was forbidden during the war.
- unrequired — to have need of; need: He requires medical care.
- discretionary — subject or left to one's own discretion.
adverb obligatory
- by choice — willingly, of one's free will
- optionally — left to one's choice; not required or mandatory: Formal dress is optional.
- voluntarily — done, made, brought about, undertaken, etc., of one's own accord or by free choice: a voluntary contribution.
- with all one's heart — Anatomy. a hollow, pumplike organ of blood circulation, composed mainly of rhythmically contractile smooth muscle, located in the chest between the lungs and slightly to the left and consisting of four chambers: a right atrium that receives blood returning from the body via the superior and inferior vena cavae, a right ventricle that pumps the blood through the pulmonary artery to the lungs for oxygenation, a left atrium that receives the oxygenated blood via the pulmonary veins and passes it through the mitral valve, and a left ventricle that pumps the oxygenated blood, via the aorta, throughout the body.
- on one's own — of, relating to, or belonging to oneself or itself (usually used after a possessive to emphasize the idea of ownership, interest, or relation conveyed by the possessive): He spent only his own money.
- of one's own accord — to be in agreement or harmony; agree.