IPA: /ˈstɪfər/
KK: /ˈstɪfər/
More rigid or inflexible than something else.
The new material is stiffer than the old one, making it more durable.
Comparative: stiffer
Superlative: stiffest
Stiffer → It is formed from "stiff" (from Old English "stif", meaning rigid or firm) and the comparative suffix "-er" (meaning more). The word "stiffer" means more rigid or firm than something else.
Think of something that is 'more rigid' — 'stiff' describes something firm, and adding '-er' shows that it is even more so.