IPA: /ˈɡrʌfər/
KK: /ˈgrʌfər/
Having a rough or stern manner, often used to describe someone's voice or attitude that is unfriendly or harsh.
The old man spoke in a gruffer tone than usual, making the children feel uneasy.
Comparative: gruffer
Superlative: gruffest
Gruffer is derived from the comparative form of the adjective "gruff" (from Middle English "gruf", meaning rough or harsh). The suffix "-er" indicates a comparative degree. Therefore, "gruffer" means more rough or more harsh than something else.
Think of someone who is 'rough' or 'harsh' ('gruff') and remember that 'gruffer' means even more so.