Itchier is the comparative form and itchiest is the superlative form.
Comparative: My new shoes are itchier than my old shoes.
Superlative: Those cheap shoes you can get at the local department stores are the itchiest shoes I've ever tried.
The comparative and superlativeforms of grand are: Comparative: grander Superlative: grandest
comparative = sadder superlative = saddest
Comparative: shallower Superlative: shallowest
The comparative is "stricter" and the superlative is "strictest".
Comparative: thinner Superlative: thinnest
comparative : purer superlative : purest
Comparative: older Superlative: oldest
Dative; Early Comparative; Earlier Superlative; Earliest
The comparative and superlativeforms of grand are: Comparative: grander Superlative: grandest
comparative - merrier superlative - merriest
comparative = sadder superlative = saddest
Comparative: shallower Superlative: shallowest
The comparative is "stricter" and the superlative is "strictest".
The comparative is greater and the superlative is greatest.
Comparative is more and superlative is most.
comparative straighter and the superlative the straightest
Comparative: thinner Superlative: thinnest