Every Saturday I’ll give you a couple of idioms to learn. An idiom is a saying or phrase whose meaning cannot be taken from the literal meanings of the words.
big gun/cheese/wheel/wig: very important person, leader in a company or group.
Example:
All the company bigwigs went on a planning retreat in Orlando over the holidays.
company man: someone who is a diligent worker, and devoted to the company.
Example:
If we hire you for this position, you will be expected to be a company man. We want people who are interested in a career, not merely a job.