ちっす・チッス : chissu | define meaning

Ultimately from the greeting こんにちは konnichiwa "hello", which was reduced to こんちは konchiwa and finally ちわ chiwa. The latter form was then combined with the colloquial ending っす -ssu (a corruption of です desu or (で)ございます (de)gozaimasu), becoming ちわっす chiwassu and finally ちーっす chiissu and ちっす chissu.