elision (en)

(linguistics) the omission of a sound or syllable when speaking OR the act or an instance of omitting something

frisson (en)

(noun) a brief moment of emotional excitement; shudder thrill

lacuna (en)

an unfilled space; a gap (plural: lacunae)

rarefied (en)

(adjective) being less dense / (adjective) of, relating to, or interesting to a select group; esoteric / (adjective) very high / (verb) to make rare, thin, porous, or less dense; to expand without the addition of matter / (verb) to make more spiritual, refined, or abstruse / (verb) to become less dense