Shopper is an agent, not a comparative. Many of the words ending in -er are comparative because they are based on a comparison like big, bigger, biggest, fast, faster, fastest. But when the word changes from an action to a person or noun then it is an agent like shopper, editor, creator, etc.
agent
a male shopper = koneh (×§×•× ×”) a female shopper = konah (×§×•× ×”)
"Litter" is a noun and a verb and, as such, does not have a comparative degree.
smoother is comparative of word smooth.
A comparative for the word ineffectual is more ineffectual.
comparative
Dative ; sharp Comparative ; sharper Superlative ; sharpest.
comparative
comparative
What's the comparative and superlative of the word "exact"
The synonym for the word "comparative" is "relative" or "analogous."
Worse is the comparative word.