IPA: /ˈprɒpərər/
KK: /ˈprɒpərər/
More suitable or appropriate than something else.
He is looking for a properer way to solve the problem.
Comparative: properer
Superlative: properest
The word 'properer' is formed from 'proper' (from Old French *propre*, meaning one's own or suitable) and the comparative suffix '-er' (meaning more). The term 'properer' means more suitable or more appropriate than something else.
Think of 'proper' meaning suitable or appropriate, and remember that adding '-er' indicates a comparison, so 'properer' means more suitable.