annihilate 1C La decimare "to kill every tenth man"
to destroy a large portion
destroy much of; kill a large part of.
kill one in every ten, as of mutineers in Roman armies
kill in large numbers; "the plague wiped out an entire population"
to reduce to ten per cent of the original population or total.
Originally meant the killing of one in 10, as the Roman legions once did to punish troops for avoiding going into battle. It should be used only to mean killing, not other destruction, and even with killings, it ideally should be reserved for cases where the idea of one in 10 isn't outlandishly off the mark.
To kill off a large part of a population.