mid-15c., "capable of being obtained for a price; that can be corrupted;" 1660s, "offered for sale," from Frenchvénal, Old Frenchvenel "for sale" (of prostitutes, etc.; 12c.) and directly from Latinvenalis "for sale, to be sold; capable of being bribed."

This is fromvenum (nominative*venus) "for sale," reconstructed to be from PIE*wes-no- "price," from root*wes- (1) "to buy, sell," source also of Sanskritvasnah "purchase money,"vasnam "reward,"vasnayati "he bargains, haggles;" Greekonos "price paid, purchase,"oneisthai "to buy."

Typically with a bad sense of "ready to sell one's services or influence for money and from sordid motives; to be bought basely or meanly."

Venal is strongest in expressing the idea of complete sale to a purchaser—character, honor, principle, and even individuality being surrendered for value received, thevenal man doing whatever his purchaser directs, avenal press advocating whatever it is told to advocate. [Century Dictionary, 1891]

c. 1300,revilen, "debase, degrade" (a sense now obsolete);" mid-14c., "insult, taunt, vilify, assail with abusive language," from Old Frenchreviler "consider vile, despise, scorn," fromre-, here perhaps an intensive prefix (seere-), +aviler "make vile or cheap, disesteem," fromvil "shameful, dishonorable; low-born; cheap; ugly, hideous" (seevile (adj.)). Related:Reviled;reviler;reviling.

c. 1500,vilifien, "to lower in worth or value, consider of little value," from Late Latinvilificare "to make cheap or base; to esteem of little value," from Latinvilis "cheap, base" (seevile) + combining form offacere "to make" (from PIE root*dhe- "to set, put"). The meaning "to abuse with slanderous language, speak evil of" is attested from 1590s. Related:Vilified,vilifying.