if you hear information by word of mouth, you hear it from other people and not from the radio or television or from reading newspapers.

I think she heard about the job by word of mouth.

• claw your way somewhere
• clean bill of health
• clean break
• Cleanliness is next to Godliness.
• clean out
• clean sheet
• clean slate
• clean someone out
• clean sweep
• clean up
• clean up act
• clean up somewhere
• clean up your act
• clear as mud
• clear-cut
• clear-eyed
• clear name
• clear out
• clear someone's name
• clear the air
• clear the decks
• clear the way
• clear the way for
• clear the way for someone
• clear the way for something