quid pro quo

noun6

1. •
   Something which is offered or asked for in exchange for something else.

   • To deny that the arrangement was a quid pro quo would be laughably disingenuous.
   • It was quite obviously a quid pro quo arrangement.
2. •
   A usually non-monetary exchange transaction, or series or process of exchange transactions.

   • The apparent exception at the Temple of Neith at Sais is likely due to an agreement, a quid pro quo, made with Udjahorresnet, not to a failure to enact the command immediately. — 2004
3. •
   An equal or fair transaction or series of process of exchange transactions; tit for tat.

   • What we should do, however, is insist that there be a quid pro quo — an equal exchange. — 1988
4. •
   Sexual harassment in which a person in a workplace implicitly or explicitly requires sexual favours in exchange for something.
5. •
   Something which is understood as something else; an equivocation.

   • The misunderstanding of the word or the quid pro quo is the unintentional pun, and is related to it exactly as folly is to wit. — 1844
6. •
   (historical) Substitution of one drug for another.

   • a knave Apothecary that administers the Physick, and makes the medicine, may doe infinite harme, by his old obsolete doses, adulterine druggs, bad mixtures, quid pro quo, etc. — 1621