Don’t create double negatives by combining a negative adjective or adverb (no, not, hardly) with another negative word.
Standard English allows two negatives only if a positive meaning is intended:
Double negatives used to convey a negative meaning are nonstandard.
Negative modifiers such as never, no, and not should not be paired with other negative modifiers or with negative words such as neither, none, no one, nobody, and nothing.
The double negative not . . . nothing is nonstandard.
The modifiers hardly, barely, and scarcely are considered negatives in standard English, so they should not be used with other negatives such as not, no one, and never.
Exercises:
Adjectives and adverbs 1
Adjectives and adverbs 2
Adjectives and adverbs 3