Likely, likelier, likeliest. You may also use the Frenchified forms, more likely and most likely. All English adjectives form the comparative in -er. Some snooty people prefer the French form for certain imported or polysyllabic adjectives, thinking that the native English comparatives "sound wrong." But even they must agree that all English adjectives ending in -y take -ier in the comparative.
comparative - merrier superlative - merriest
Frequency is a noun and doesn't have a comparative or superlative form.Frequent is an adjective and the comparative form is more frequent and the superlative form is most frequent
comparative=tenser superlative =tensest
The comparative form of tight is "tighter". The superlative form is "tightest".
The comparative form of tinny is tinnier, and the superlative form is tinniest.
More doubtful, most doubtful moister, moistest
comparative - merrier superlative - merriest
The comparative form of cloudy is "cloudier". The superlative form is "cloudiest".
"Older" is the comparative form of old. The superlative form is oldest.
more doubtful, most doubtful more wooden, most wooden
The comparative is grumpier and the superlative is grumpiest.
"Bit" is a noun and a verb and, as such, does not have a comparative or superlative form.
Sweetie is a noun and does not have a comparative or superlative form.
Comparative: older Superlative: oldest
well (healthy) comparative is better and superlative is the best
The comparative form of easy is easier, and the superlative form is easiest.
The comparative form of gloomy is gloomier, the superlative form is gloomiest.