Consultant
Part of speech: noun
Definition: a person or party that is consulted. a person whose occupation is to be consulted for their expertise, advice, or help in an area or specialty. Alternatively, a party whose business is to be similarly consulted.
Example sentence: We live in a culture that's been hijacked by the management consultant ethos. We want everything boiled down to a Power Point slide. We want metrics and 'show me the numbers.' That runs counter to the immensely complex nature of so many social, economic and political problems. You cannot devise an algorithm to fix them.
Advisor
Part of speech: noun
Definition: One who offers advice.
Example sentence: When I entered college, I wasn't sure what I was going to do. My advisor happened to be from the theater department, and he encouraged me to take some classes there, which I did.