That would be "common".
antonym
common
Yes
Un unique different
odd unique strange abnormal
Usual, common, etc ....
I believe that counteroffer is a unique word with no antonyms or synonyms.
An antonym for "unique" is "common." While "unique" refers to something that is one of a kind or distinct, "common" describes something that is widespread or frequently encountered. Other possible antonyms include "ordinary" or "typical."
Depending on the application; novel, new, innovative, unique, singular
Different, or a change. extraordinary. special, unique
The antonym of "custom" is "standard" or "norm." While "custom" refers to practices or habits that are unique to a particular group or individual, "standard" denotes something that is widely accepted or established as a norm.
Synonyms: characteristic, peculiarity, quirk, eccentricityAntonyms: commonality