It's "shorts are". It's not correct to say "short is" because this noun only has a plural form, and requires a plural form of a verb.
It's "shorts are". It's not correct to say "short is" because the noun "shorts" only has a plural form, and requires a plural form of a verb.
Your shorts are too big.
Your shorts is too big.
You can use the expression "a pair of shorts" to refer to a single entity. This expression, however, requires a singular form of a verb.
There is a pair of shorts in the drawer. (not "There are...")
When using other verbs, such as look, have, fit, etc., follow the same convention.
Your shorts have a grass stain. (not "has a grass stain...")
Be also aware that we always use a plural determiner or pronoun (they, these, those, etc.) with this word.
Those shorts are trendy! Where did you buy them?
A partial list of clothing-related nouns that only have a plural form, and therefore take "are", can be found below: