Question

one word substitution of one who offer one services

Answer 1

A volunteer offers one's services.

Answer 2

Answer :

One word substitution tests our ability to express the meaning of a phrase or a clause in a single word. These tests are helpful in determining the vocabulary and communication skills of an individual.

Cambridge English Dictionary defines 'volunteer' as 'a person who does something, especially helping other people, willingly and without being forced or paid to do it.'

So, one word substitution of 'one who offer one services' is volunteer.