plural guards
1
: a state in which someone is carefully looking for possible danger, threats, problems, etc.
There were dozens of police officers standing/keeping guard along the parade route.
Several soldiers were on guard [=watching and ready to respond if needed] at the gate.
The soldiers were on their guard. [=they were watching and ready to respond]
We need to be on guard against attack. [=we need to be alert so we are not attacked; we should be prepared to be attacked]
He always has/keeps his guard up [=is careful and alert] during negotiations.
She never lets down her guard. = She never lets her guard down. [=she never relaxes and stops being careful and alert]
2
a
: a person whose job or duty is to watch and protect someone or something
There were several (armed) guards stationed at the gate.
(US) a prison guard [=someone who watches prisoners to prevent their escape]
b
: a group of people (such as soldiers) who protect a person or place
the palace guard
Tourists gather every day to watch the changing of the guard at Buckingham Palace.
c
: soldiers who protect a king or queen
the Royal Horse Guards
3
a
: something that keeps an unwanted result or effect from happening
—often + against
The wound should be thoroughly cleaned as a guard against infection.
b
: a special part or device that protects someone or something from injury or damage
The guard must be in place before operating the meat slicer.
a mouth/shin guard
4
a
American football
: either one of two players who play in positions on either side of the center
b
basketball
: either one of two players who usually play away from the basket and control their team's play when they are trying to score points
5
British
: conductor sense 2
guards; guarded; guarding
1
: to watch (someone) in order to prevent escape
Two policemen were assigned to guard the prisoner.
2
: to protect (someone or something) from danger or attack
soldiers guarding the president
A tank guarded the bridge from/against enemy attack.
A police officer was stationed outside to guard the door/entrance.
3
: to be careful about not telling or talking about (something, such as a secret)
They jealously guard their secrets.
He guards his privacy.
Her whereabouts are a tightly/closely guarded secret.
4
sports
: to try to keep (an opponent) from scoring (especially in basketball)
He was assigned to guard their best player.
Cite this Entry
“Guard.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/guard. Accessed 19 Jun. 2026.
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