fly-tip 
verb [no object] British
Illegally dump waste.The government also announced new measures to control illegal dumping of waste, known as fly-tipping....
- By charging people for household waste, wouldn't this lead to an increase in fly-tipping?
- Some businesses now prefer to risk fly-tipping rather than dispose of their waste in the normal way.
Derivatives
fly tipper
- But at 5.30 pm the same day the fly-tippers were back filling it up again with beds, doors and carpets.
- We urge anybody not to tackle fly-tippers but to note the vehicle registration number and report it to the council.
- Clearing up after fly-tippers costs the Council a lot of time and money each year and we are determined to catch those who do it.
Origin
1960s: from on the fly at fly1.