The comparative form of rude is ruder, and the superlative form is rudest. It is common to form the comparative and superlative of short words like this by adding -er and -est.
The comparative form of risky is riskier, and the superlative form is riskiest. The word risky is short enough to form the comparative and superlative forms this way. For longer words, you would need to precede the word with more (for comparative) and most (for superlative).
I believe for words such as foolish you need to use more and most. Comparative: More Foolish Superlative: Most Foolish
comparative - merrier superlative - merriest
comparative = tenderer superlative = tenderest
"Higher" is the comparative of high. The superlative is highest.
Comparative: lazier Superlative: laziest
'Next' is a superlative; it means 'nearest'. The positive is therefore 'near' and the comparative is 'nearer'.
last
harmful
Comparative: easier Superlative: easiest
The comparative form of rude is ruder, and the superlative form is rudest. It is common to form the comparative and superlative of short words like this by adding -er and -est.
finer, finest
older, oldest
stronger and strongest
busier, and busiest
For words of two syllables not ending in y, use more for the comparative and most for the superlative.