informal

something that you say when you want someone to repeat what they have just said because you did not hear or understand it.

'What's amazing is that Pauline's half sister's son is the father of her cousin's child.' 'Come again?'

• on the same lines
• on the same page
• on the same wavelength
• on the scene
• on the scrap heap
• on the shelf
• on the side
• on the sidelines
• on the side of the angels
• on the sly
• on-the-spot
• on the spot
• on the spur of the moment
• on the starting blocks
• on the strength of
• on the strength of something
• on the stump
• on the table
• on the threshold of
• on the threshold of something
• on the tip of tongue
• on the tip of your tongue
• on the town
• on the trot
• on the verge of