1. to make or become smooth or smoother
Usage: primarily used in Indian English and some other varieties; less common in American English where ‘smooth’ is typically used as a verb

Examples

• She used sandpaper to smoothen the wooden surface.
• The cream helps smoothen rough skin.
• Time will smoothen the rough edges of their relationship.
• The road crew worked to smoothen the bumpy pavement.
• Regular moisturizing can smoothen dry, cracked hands.
• The artist used a brush to smoothen the paint strokes.