Limit, restrict, circumscribe, confine mean to set or prescribe the bounds for a person or thing.
Limit usually implies the predetermination of a point (as in time, in space, in quantity, in capacity, or in production) beyond which the person or thing concerned cannot go or is not permitted to go without suffering a penalty or incurring undesirable consequences. But limit may also be used with reference to a bound or bounds not predetermined but inherent in a situation or in the nature or constitution of a thing or brought about as desirable by conscious effort or by full choice.
Restrict, in contrast to limit, suggests a boundary that encircles and encloses rather than a point that ends; the term therefore often applies to something which can be thought of in the terms of the space, territory, or field that it covers. The word often also connotes a narrowing or tightening.
Circumscribe differs from restrict in that its implication of an encircling or enclosing boundary is always clear; consequently, it is often preferred to restrict when the idea of being kept within too small an extent or range is to be stressed or when there is the intent to suggest a distinct, complete, but limited whole and its apartness from all that surrounds it.
Confine may imply limitation, restriction, or circumscription, but it usually emphasizes the bounds which must not or cannot be passed; consequently, it often suggests severe restraint or restraints and carries connotations such as those of cramping, fettering, hampering, or bottling up that are not often present in the other words.