"servile or insincere praise," late 14c., from Old French adulacion, from Latin adulationem (nominative adulatio) "a fawning; flattery, cringing courtesy," noun of action from past-participle stem of adulari "to flatter, fawn upon."
This is usually said to be from ad "to" (see ad-) + a stem meaning "tail," from a PIE *ul- "the tail" (source also of Sanskrit valah "tail-hair," and Lithuanian valai "horse's tail"). The original notion would be "to wag the tail" like a fawning dog (compare Greek sainein "to wag the tail," also "to flatter;" also see wheedle).
But de Vaan finds phonetic problems with these and concludes the etymology is uncertain, though he proposes a connection with avidus "eager," via *adulo- "who is eager toward something," hence "a flatterer." Adulation may proceed from true blind worship or be insincere, from hope of advantage.
early 15c., palpitacioun, "rapid movement, trembling or quivering motion," from Latin palpitationem (nominative palpitatio), noun of action from past-participle stem of palpitare "to throb, to flutter, to tremble, to quiver," frequentative of palpare "touch gently, stroke; wheedle, coax" (see palpable). Specifically of unnatural rapid beating or pulsation of the heart (excited by emotion, disease, etc.) by c. 1600.
"deceive or delude by flattery," 1640s, from French cajoler "to cajole, wheedle, coax," a word of uncertain origin; perhaps a blend of cageoler "to chatter like a jay" (16c., from gajole, southern diminutive of geai "jay;" see jay (n.)), and Old French gaioler "to cage, entice into a cage" (see jail (n.)). Related: Cajoled; cajoling.