The difference between Fender and Guard

Fender as a noun (US):

Panel of a car which encloses the wheel area, especially the front wheels.

Fender as a noun (US):

A shield, usually of plastic or metal, on a bicycle that protects the rider from mud or water.

Fender as a noun (nautical):

Any shaped cushion-like object normally made from polymers, rubber or wood that is placed along the sides of a boat to prevent damage when moored alongside another vessel or jetty, or when using a lock, etc. Modern variations are cylindrical although older wooden version and rubbing strips can still be found; old tyres are used as a cheap substitute.

Fender as a noun:

A low metal framework in front of a fireplace, intended to catch hot coals, soot, and ash.

Fender as a verb (nautical):

To use fenders to protect the side of a boat

Guard as a noun:

A person who, or thing that, protects or watches over something.

Guard as a noun (Ireland):

A garda; a police officer.

Guard as a noun (military):

A squad responsible for protecting something.

Guard as a noun:

The part of a sword that protects the wielder's hand

Guard as a noun:

A part of a machine which blocks access to dangerous parts.

Guard as a noun (Australia):

A panel of a car that encloses the wheel area, especially the front wheels.

Guard as a noun (basketball):

A relatively short player, playing farther from the basket than a forward or center.

Guard as a noun (cricket):

The position on the popping crease where a batsman makes a mark to align himself with the wicket; see take guard.

Guard as a noun (American football):

Either of two offensive positions between the center and each of the offensive tackles, whose main responsibilities are to protect the quarterback, and open up "holes" through which offensive players can run.

Guard as a noun (sports):

A player playing a position named guard.

Guard as a noun (rail):

An employee, normally travelling in the last vehicle of a train, responsible for the safety of the train.

Guard as a noun (computing, programming):

A Boolean expression that must evaluate to true for a branch of program execution to continue.

Guard as a verb:

To protect from danger; to secure against surprise, attack, or injury; to keep in safety; to defend.

Guard as a verb:

To keep watch over, in order to prevent escape or restrain from acts of violence, or the like.

Guard as a verb:

To watch by way of caution or defense; to be caution; to be in a state or position of defense or safety.

Guard as a verb:

To protect the edge of, especially with an ornamental border; hence, to face or ornament with lists, laces, etc.

Guard as a verb:

To fasten by binding; to gird.