assistant

Having a subordinate or auxiliary position.

an assistant surgeon

Helping; lending aid or support; auxiliary.

Genius and learning […] are mutually and greatly assistant to each other.

The person principally assistant on this occasion, indeed the only one who did any service, or seemed likely to do any, was the landlady […]

Someone who is present; a bystander, a witness.

a woman of great authority, having first yeelded an accompt unto her Citizens, and shewed good reasons why she was resolved to end her life, earnestly entreated Pompey to be an assistant at her death, that so it might be esteemed more honourable[…].

A person who assists or helps someone else.

Sales assistant.

A software tool that provides assistance in some task, a wizard program.