Nudum pactum

contract that cannot be enforced because on side benefits without putting forth any effort

A nudum pactum in Latin literally means 'Bare or Naked Promise.' In common law, it refers to a promise that is not legally enforceable for want of consideration. An example of a nudum pactum would be an offer to sell something without a corresponding offer of value in exchange. Since the offer has not been created with any consideration, it is gratuitous and treated as a unilateral contract. The offer is therefore revocable at any time by the offeror before acceptance by the offeree.
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nudum pactum, contract that cannot be enforced because on side benefits without putting forth any effort (Latin)

A bare, naked contract, without any consideration.
  

A contract-law term which stands for those agreements which are without consideration, such as a unilateral undertaking, which may bind a person morally, but not under contract law, in those jurisdictions which still require consideration. - (read more on Nudum pactum)