Decimating meaning : To kill one-tenth of a group, (specifically) as a military punishment in the Roman army selected by lot, usually carried out by the surviving soldiers. To destroy or remove one-tenth of anything. To devastate: to reduce or destroy significantly but not completely. To exact a tithe or other 10% tax To tithe: to pay a 10% tax. To decimalize: to divide into tenths, hundredths etc. To reduce to one-tenth: to destroy or remove nine-tenths of anything. To replace a high-resolution model with another of lower but acceptable quality.