amiss adv.

prefix or inseparable particle, a conglomerate of various Germanic and Latin elements.

In words derived from Old English, it commonly represents Old English an "on, in, into" (see on (prep.)), as in alive, above, asleep, aback, abroad, afoot, ashore, ahead, abed, aside, obsolete arank "in rank and file," etc., forming adjectives and adverbs from nouns, with the notion "in, at; engaged in." In this use it is identical to a (2).

It also can represent Middle English of (prep.) "off, from," as in anew, afresh, akin, abreast. Or it can be a reduced form of the Old English past participle prefix ge-, as in aware.

Or it can be the Old English intensive a-, originally ar- (cognate with German er- and probably implying originally "motion away from"), as in abide, arise, awake, ashamed, marking a verb as momentary, a single event. Such words sometimes were refashioned in early modern English as though the prefix were Latin (accursed, allay, affright are examples).

In words from Romanic languages, often it represents reduced forms of Latin ad "to, toward; for" (see ad-), or ab "from, away, off" (see ab-); both of which by about 7c. had been reduced to a in the ancestor of Old French. In a few cases it represents Latin ex.

[I]t naturally happened that all these a- prefixes were at length confusedly lumped together in idea, and the resultant a- looked upon as vaguely intensive, rhetorical, euphonic, or even archaic, and wholly otiose. [OED]

Old English missan "fail to hit, miss (a mark); fail in what was aimed at; escape (someone's notice)," from Proto-Germanic *missjan "to go wrong" (source also of Old Frisian missa, Middle Dutch, Dutch missen, German missen "to miss, fail"), from *missa- "in a changed manner," hence "abnormally, wrongly," from PIE root *mei- (1) "to change, go, move." Reinforced or influenced by cognate Old Norse missa "to miss, to lack." Related: Missed; missing.

Sense of "fail to find" (someone or something) is by late 12c. Meaning "fail to note, perceive, or observe" is from early 13c. Meaning "fail to reach or attain what one wants" is from mid-13c. Sense of "perceive with regret the absence or loss of (something or someone)" is from c. 1300. Meaning "omit, leave out, skip" is by mid-14c. Sense of "to escape, avoid" is from 1520s.

Sense of "to not be on time for" is from 1823; to miss the boat in the figurative sense of "be too late for" is from 1929, originally nautical slang. To miss out (on) "fail to get" is by 1929.