: not proper, right, or suitable: such as
a
: not correct
The doctor gave him an improper diagnosis.
improper grammar
b
: not following rules of acceptable behavior : legally or morally wrong
They claim to have evidence of improper police conduct.
improper use of public land
c
: not suitable for the situation : not appropriate
This is an improper diet for a growing teenager.
improper dress/attire
d
: not polite
It would be improper for me to ask such a favor of her.
He made some improper remarks.
improper behavior
Cite this Entry
“Improper.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/improper. Accessed 22 Jun. 2026.
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