o·ver·kill 
(ōvər-kĭl′)
(ōvər-kĭl′)n.
1. The destructive use of military force beyond the amount needed to destroy an enemy.
2. The excessive use of force in killing an individual or organism.
3. Elimination or drastic reduction of an animal population by hunting or killing.
4. An excess of what is necessary or appropriate for a particular end: "government overkill in dealing with dissent" (Jesse Unruh).
v. (ō′vər-kĭl) o·ver·killed, o·ver·kill·ing, o·ver·kills
v.tr.
1. To destroy (an enemy or enemy target) with more force than necessary.
2. To use excessive force in killing (an individual, for example).
3. To kill too many of (a population of animals) for the population to maintain itself in substantial numbers.
4. To apply an excess of what is necessary or appropriate for (a particular end): overkill an advertising campaign.
v.intr.
To engage in overkill.