repaint v.

word-forming element meaning "back, back from, back to the original place;" also "again, anew, once more," also conveying the notion of "undoing" or "backward," etc. (see sense evolution below), c. 1200, from Old French re- and directly from Latin re- an inseparable prefix meaning "again; back; anew, against."

Watkins (2000) describes this as a Latin combining form conceivably from Indo-European *wret-, metathetical variant of *wert- "to turn." De Vaan says the "only acceptable etymology" for it is a 2004 explanation which reconstructs a root in PIE *ure "back."

In earliest Latin the prefix became red- before vowels and h-, a form preserved in redact, redeem, redolent, redundant, redintegrate, and, in disguise, render (v.). In some English words from French and Italian re- appears as ra- and the  following consonant is often doubled (see rally (v.1)).

The many meanings in the notion of "back" give re- its broad sense-range: "a turning back; opposition; restoration to a former state;" "transition to an opposite state." From the extended senses in "again," re- becomes "repetition of an action," and in this sense it is extremely common as a formative element in English, applicable to any verb. OED writes that it is "impossible to attempt a complete record of all the forms resulting from its use," and adds that "The number of these is practically infinite ...."   

Often merely intensive, and in many of the older borrowings from French and Latin the precise sense of re- is forgotten, lost in secondary senses, or weakened beyond recognition, so that it has no apparent semantic content (receive, recommend, recover, reduce, recreate, refer, religion, remain, request, require). There seem to have been more such words in Middle English than after, e.g. recomfort (v.) "to comfort, console; encourage;" recourse (n.) "a process, way, course." Recover in Middle English also could mean "obtain, win" (happiness, a kingdom, etc.) with no notion of getting something back, also "gain the upper hand, overcome; arrive at;" also consider the legal sense of recovery as "obtain (property) by judgment or legal proceedings." 

And, due to sound changes and accent shifts, re- sometimes entirely loses its identity as a prefix (rebel, relic, remnant, restive, rest (n.2) "remainder," rally (v.1) "bring together"). In a few words it is reduced to r-, as in ransom (a doublet of redemption), rampart, etc.

It was used from Middle English in forming words from Germanic as well as Latin elements (rebuild, refill, reset, rewrite), and was used so even in Old French (regret, regard, reward, etc.).

Prefixed to a word beginning with e, re- is separated by a hyphen, as re-establish, re-estate, re-edify, etc. ; or else the second e has a dieresis over it: as, reëstablish, reëmbark, etc. The hyphen is also sometimes used to bring out emphatically the sense of repetition or iteration : as, sung and re-sung. The dieresis is not used over other vowels than e when re is prefixed : thus, reinforce, reunite, reabolish. [Century Dictionary, 1895]

mid-13c., peinten, "represent (someone or something) in paint;" c. 1300, "decorate (something or someone) with drawings or pictures;" early 14c., "put color or stain on the surface of; coat or cover with a color or colors;" from Old French peintier "to paint," from peint, past participle of peindre "to paint," from Latin pingere "to paint, represent in a picture, stain; embroider, tattoo," from a nasalized form of PIE root *peig- "to cut, mark by incision."

The sense evolution between PIE and Latin was, presumably, "decorate with cut marks" to "decorate" to "decorate with color." Compare Sanskrit pingah "reddish," pesalah "adorned, decorated, lovely;" Old Church Slavonic pegu "variegated;" Greek poikilos "variegated;" Old High German fehjan "to adorn;" Old Church Slavonic pisati, Lithuanian piešiu, piešti "to write." Probably also representing the "cutting" branch of the family is Old English feol (see file (n.2)).

From late 14c. as "represent persons and things in pictures or drawing, portray." To paint the town (red) "go on a boisterous or disorderly spree" is by 1884; to paint (someone or something) black "represent it as wicked or evil" is from 1590s. Adjective paint-by-numbers "simple" is attested by 1970; the art-for-beginners kits themselves date to c. 1953.