adv. 1 collog. very much (enjoyed myself immensely). 2 to an immense degree (immensely rich). immerse itma:si v. (sing) 1 a (often foil. by in) dip, plunge. b submerge (a person). 2 (often refl. or in passive; often foil. by in) absorb or involve deeply. 3 (often foil. by in) bury, embed. [Latin mergo mers dip]