'Yesterday' is not an adjective and does not have a comparative degree. It means 'the day immediately before today'. Something cannot happen on 'the day more immediately before today' - it makes no sense.
Expressions such as 'the day before yesterday', 'a week ago yesterday', and so on, are used to indicate dates further in the past, but they do not constitute the comparative degree.
"Yesterday" is an adverb indicating a specific point in time, not an adjective that can have a comparative form.
better for its comparative and best for its superlative
The comparative degree form of "pitiful" is "more pitiful."
comparative degree: more truthful superlative degree: most truthful
The comparative degree for "lush" is "lusher."
The comparative degree of "muddy" is "muddier".
The comparative degree of the word "honest" is "more honest."
better for its comparative and best for its superlative
The answer is comparative.
"Litter" is a noun and a verb and, as such, does not have a comparative degree.
more out
more out
The comparative degree is 'more magnificent' and the superlative degree is 'most magnificent'.
The comparative degree form of "pitiful" is "more pitiful."
abler
sicker
nicer
finer, finest