"moisten and rub (a bruised or injured part of the body) with a liquid substance," 1610s, from Medieval Latin embrocatus, past participle of embrocare, from Late Latin embrocha, from Greek embrokhe "lotion, fomentation," from embrekhein "to soak in, foment," from assimilated form of en (see en- (2)) + brekhein "to water, wet, rain, send rain," related to brokhe "rain," from PIE root *mergh- "to wet, sprinkle, rain." Related: Embrocated; embrocating; embrocation (early 15c.).
1630s, "itching," later, and now exclusively, "having an itching desire for something" (1650s), especially "lascivious, inclined to lewd thoughts," (1746), from Latin prurientem (nominative pruriens), present participle of prurire "to itch; to long for, be wanton," which is perhaps related to pruna "glowing coals" (from PIE root *preus- "to freeze; to burn;" see freeze (v.)).
De Vaan suggests a source in PIE *preus-i-, *prus-no-"(cold and) wet; itching," source also of Welsh rhew, Breton rev, reo "frost," Sanskrit prushnuvanti "to (be)sprinkle, wet," and writes that "The meaning 'to be wet, itch' was metaphorically also applied to high temperatures, hence 'burning' in pruna." But it needn't be metaphorical: Cold damage to skin is called ice burn and the paradoxical sensation of burning when the skin contacts an extreme cold surface has long been noted. Related: Pruriently.
1550s, "to dip a little and often," hence "to wet by splashing," probably a frequentative of dab. Figurative sense of "do superficially" attested by 1620s. Related: Dabbled; dabbling. An Ellen Dablewife is in the Lancashire Inquests from 1336.
"small puddle, shallow pool, wet ground," Old English plæsc "pool of water, puddle," probably imitative (compare plash (v.1) and Dutch plass "pool"). Meaning "noise made by splashing" is recorded by 1510s. Related: Plashy.