adviser

Etymology
From.

Noun

 * 1) one who advises

Usage notes

 * In the UK, Ireland and Asia the spelling is traditionally adviser, though US spelling advisor  is becoming increasingly common. In the US, Associated Press style is adviser, and most newspapers and some magazines follow that spelling, whereas US federal government style, other government agencies, and many businesses prefer advisor. News organizations around the world may change spelling found in sources, even in quoted material. US book publishers may be less likely to change spelling in quoted material because this practice is contrary to The Chicago Manual of Style.

Etymology
, with the added back to reflect the.

Verb

 * 1) to advise; to counsel