External is an absolute. There cannot be comparative or superlative forms.
Lainey is the smartest.
absolute adjectives
Amicíssimo in Spanish
The word "worthwhile" does not have a commonly used comparative or superlative form, as it is often considered an absolute term. However, if you need to express a comparison, you might use phrases like "more worthwhile" for the comparative and "most worthwhile" for the superlative. These constructions maintain the meaning of the original term while indicating degrees of worth.
For adjectives of three syllables or more, put "more" in front of them for the comparative and "most" for the superlative.
In music, the tempo marking prestissimo means "as fast as possible."
comparative: more interesting superlative: the most interesting
Yes, it can be. Worst can be a superlative adjective or a superlative adverb (meaning most badly).
Opposite is an absolute. There cannot be something which is more or most opposite.
Superlative: Scratchiest, meaning the most scratchy. Comparative: Scratchier, meaning more scratch (but not necessarily the most).
The comparative - "upper"; I can't think of any superlative.