noun
plural dents
[count] :an area on a surface that is lower than the rest of the surface especially because of being hit or pushed in
make/put a dent
In figurative use, to make a dent (in something) or to put a dent in something is to decrease something slightly or to make it somewhat weaker.
verb
dents; dented; denting
to make a dent in (something) [+ obj]
[+ obj] :to decrease (something) :to make (something) weaker