Here are 5 words with replacements that have either a positive or negative connotation:
1. Mother
Positive connotation: Caregiver
Negative connotation: Nag
2. Pencil
Positive connotation: Writing tool
Negative connotation: Broken stub
3. Book
Positive connotation: Page-turner
Negative connotation: Doorstop
4. Movie
Positive connotation: Blockbuster
Negative connotation: Snoozefest
5. Dog
Positive connotation: Man's best friend
Negative connotation: Mutt