Let one’s guard down and drop one’s guard are two variations of an idiom that may not be as old as you think. We will examine the meaning of the common sayings let one’s guard down and drop one’s guard, where they came from, and some examples of their idiomatic usage in sentences.
Let one’s guard down and drop one’s guard are expressions that both mean to relax, to stop being vigilant, to be less careful, to be less alert. The idioms let one’s guard down and drop one’s guard invoke the imagery of relaxing a military stance or lowering one’s weapon. The expressions let one’s guard down and drop one’s guard, in a figurative sense, seem to have only become popular in the mid-twentieth century, though the phrases have been in use in a literal sense for many years before that. The phrase let one’s guard down is about twice as common as drop one’s guard.
If not for your own health, for the sake of others’ do not let your guard down – not for a minute. (Minot Daily News)
“Don’t let your guard down at any cost even though you have been vaccinated.” (Times of India)
It’s 2020, and yes the year is almost over, but don’t drop your guard now. (Houstonia Magazine)
DON’T DROP YOUR GUARD THIS CHRISTMAS, CAUTIONS BOSTIC (Barbados Advocate)