1. Secretly inform on someone; tell tales on
   "Police in Western Australia's south-west and Great Southern regions are encouraging community members to support this week's 'dob in a burglar' campaign"; "he dobbed in Hazaras to the Immigration Department"

Derived forms: dobs, dobbed, dobbing

• on tap
• on tenterhooks
• on that
• on that point
• on the average
• on the ball
• on the button
• on the coattails
• on the contrary
• on the dot
• on the face of it
• on the fence
• on the fly
• on the go
• on the hook
• on the house
• on the level
• on the line
• on the loose
• on the mend
• on the nail
• on the nose
• on the off chance
• on the offensive
• on the one hand