To obviate something (usually a need for something, or a necessity) is to anticipate and prevent it. A formal word, obviate can also mean "to make an action unnecessary."

// The new medical treatment obviates the need for surgery.

// Allowing workers flexibility should obviate any objections to the change.

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"In 1987, a new kind of computer workstation debuted from Sun Microsystems. These workstations, as well as increasingly powerful desktop computers from IBM and Apple, obviated the need for specialized LISP machines. Within a year, the market for LISP machines evaporated."

It's most often needs that get obviated. And a need that's obviated is a need that's been anticipated and prevented. That sentence may obviate your need to consult the definition again, for example. Obviate comes ultimately from the Latin adjective obviam, meaning "in the way," and obviating does often involve figuratively putting something in the way, as when an explanatory sentence placed just so blocks a need to consult a definition. (Obviam is also an ancestor of our adjective obvious.) Obviate has a number of synonyms in English, including prevent, preclude, and avert, which all can mean "to hinder or stop something." Preclude often implies that a degree of chance was involved in stopping an event, while avert always implies that a bad situation has been anticipated and prevented or deflected by the application of immediate and effective means. Obviate generally suggests the use of intelligence or forethought to ward off trouble.