imperceptibly

As an adverb imperceptibly

is not noticeably, too small to be detected, too little to be perceived.

As an adjective imperceptible is

not perceptible, not detectable, too small in magnitude to be observed.

As a adjective perceived

is generally recognized to be true.

As a verb perceived

is (perceive).

As a adverb imperceptibly is

not noticeably, too small to be detected, too little to be perceived.

As a adjective detected

is referring to something that has been noticed.

As a verb detected

is (detect).

As a adverb imperceptibly is

not noticeably, too small to be detected, too little to be perceived.

As adverbs the difference between noticeably and imperceptibly

is that noticeably is (manner) in a noticeable way while imperceptibly is not noticeably, too small to be detected, too little to be perceived.

As a adverb imperceptibly

is not noticeably, too small to be detected, too little to be perceived.

As a verb insinuate is

(rare) to creep, wind, or flow into; to enter gently, slowly, or imperceptibly, as into crevices.

As a adverb imperceptibly

is not noticeably, too small to be detected, too little to be perceived.

As a adjective instantaneous is

occurring]], [[arise|arising, or functioning without any delay; happening within an imperceptibly brief period of time.