Contract in the simplest definition is "a promise enforceable by law". The promise may be to do something or to refrain from doing something. The making of a contract requires the mutual assent of two or more persons, one of them ordinarily making an offer and another accepting. If one of the parties fails to keep the promise, the other is entitled to legal redress. The law of contracts considers such questions as whether a contract exists, what the meaning of it is, whether a contract has been broken, and what compensation is due the injured party.
Much of the law of contract is concerned with ensuring that agreements are arrived at in a way that meets at least minimum standards respecting both parties’ understanding of, and freedom to decide whether to enter into, the transactions. Such provisions include rules that void contracts made under duress or that are unconscionable bargains; protection for minors and incompetents; and formal requirements protecting against the ill-considered assumption of obligation. Thus, section 138 of the German Civil Code renders void any contract “whereby a person profiting from the distress, irresponsibility, or inexperience of another” obtains a disproportionately advantageous bargain. In addition, more general social requirements and views impinge upon contracts in a number of ways. Certain agreements are illegal, such as—in the United States—agreements in restraint of trade. Others, such as an agreement to commit a civil wrong, are held by the courts to be contrary to the public interest. Certain systems discourage some purposes, such as the assumption of a legally binding obligation to confer a gift of money or other gratuitous benefit upon another, by various special requirements.
Many contracts involve more than two persons. The law of contracts provides special rules for regulating claims by multiparty plaintiffs or claims against multiparty defendants, or for determining rights among the parties. Multiparty problems arise in other contexts as well. There is the problem of whether the immediate parties to a contract can enter into an agreement that will confer rights upon a person not an original party to the contract. Probably because the dogmatic structure of contract law was largely formed on the model of the simpler two-party situation, and because the contract for the benefit of third parties did not have great practical importance until such relatively modern developments as the emergence of life insurance, many systems of contract law have encountered difficulty in working out the relationship between the third party and the underlying contract. English law took the view that, as a rule, persons cannot acquire a right on a contract to which they are not a party.
Under Nigerian law, a contract is unenforceable if it has a vitiating element. Vitiating elements in a contract are mistakes of facts, duress, illegality, undue influence, misrepresentation, and incapacity.
A lawyer is the best guide to understanding the intricacies of a contractual agreement, putting your interest at an advantage at all times.