guard

As a noun guard

is a person who, or thing that, protects or watches over something.

As a verb guard

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

As an adjective watchful is

observant, vigilant and aware.

As verbs the difference between guard and attend

is that guard is to protect from danger; to secure against surprise, attack, or injury; to keep in safety; to defend while attend is ("to kindle") or attend can be (archaic|transitive) to listen to (something or someone); to pay attention to; regard; heed.

As a noun guard

is a person who, or thing that, protects or watches over something.

As nouns the difference between doorkeeper and guard

is that doorkeeper is the person in charge of an entryway, sometimes just a doorman, sometimes something more while guard is a person who, or thing that, protects or watches over something.

As a verb guard is

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

As nouns the difference between policeman and guard

is that policeman is a member of a police force, especially one who is male while guard is a person who, or thing that, protects or watches over something.

As a verb guard is

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

As verbs the difference between guard and maintain

is that guard is to protect from danger; to secure against surprise, attack, or injury; to keep in safety; to defend while maintain is (obsolete|transitive) to support (someone), to back up or assist (someone) in an action.

As a noun guard

is a person who, or thing that, protects or watches over something.

As nouns the difference between guard and safekeeping

is that guard is a person who, or thing that, protects or watches over something while safekeeping is the act of keeping something safe; protection from harm, damage, loss, or theft.

As a verb guard

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

As nouns the difference between officer and guard

is that officer is (senseid)one who has a position of authority in a hierarchical organization, especially in military, police or government organizations while guard is a person who, or thing that, protects or watches over something.

As verbs the difference between officer and guard

is that officer is to supply with officers while guard is to protect from danger; to secure against surprise, attack, or injury; to keep in safety; to defend.

As nouns the difference between guard and police

is that guard is a person who, or thing that, protects or watches over something while police is policy (contract of insurance).

As a verb guard

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

As verbs the difference between guard and guarded

is that guard is to protect from danger; to secure against surprise, attack, or injury; to keep in safety; to defend while guarded is past tense of guard.

As a noun guard

is a person who, or thing that, protects or watches over something.

As an adjective guarded is

cautious; restrained.

Defense is a related term of guard.

As nouns the difference between defense and guard

is that defense is defence (action of defending or protecting from attack, danger or injury, or any means for that purpose) while guard is a person who, or thing that, protects or watches over something.

As a verb guard is

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