A crutch is a figure of speech that describes something that is used as a surrogate or substitute for a more ideal solution or approach, as in the use of medical crutches as an assistance device for walking. The term also implies a degree of habitual laziness.

Intelligence agency term for "psychological operation". A government or corporate-sponsored operation, usually taking the form of a "terrorist attack" or "crazed gunman on a spree", with the intent of panicking the public into demanding more police and laws inhibiting freedom. Psyops are usually carried out by drugging a civilian or group of civilians with aggression-promoting drugs, psyching them up, arming them, and sending them out to commit mayhem. Government-sponsored terrorism. See also blackshirts, conspiracy

From a gaming perspective, a crutch is the use of an item or technique that is considered easier or generally way better than most options available. As if using a "three-wheeled bike" compared to a "two-wheeled bike"

Deathly pre-evolved devices with the purpose of aiding one with an injured leg, knee, ankle, etc.

May cause drowsiness, sweating, and result in massive upper-body strength.
ultimately, makes one look like a badass god/goddess capable of surviving any difficult circumstance.

Something that is necessary but impedes one from doing better.

A girl or boy who uses a friend of the opposite sex for comfort when there boyfriend/girlfriend are fighting with them. Then once everything is over, they become non-existant again