know (someone/something) by sight

to recognize someone or something.

I've never spoken to him, but I know him by sight.

Usage notes: usually used to suggest that you know what someone looks like but not what type of character someone has

• lend a hand
• lend a helping hand
• lend an ear
• lend an ear to
• lend an ear to someone
• lend an ear to something
• lend itself to
• lend itself to something
• lend someone a hand
• leopard can't change its spots.
• leopard doesn't change its spots.
• lesser of two evils
• less than
• less than something
• let alone
• let alone do something
• let be
• let bygones be bygones
• Let bygones be bygones.
• let down
• let fly
• let fly something
• let fly with
• let fly with something
• let go