Looking for an adjective that describes a person who lets authority, power and/or success get to their head, and as a result, start taking their power/status for granted, behaving as if they are superior, and look down on people who either were once their equals/friends or people who currently have the same status as they once did but now treat them as their inferiors.
I don't believe any of the following is sufficient: egotistical, conceited, arrogant, prideful.
An example would be a person who got promoted from being an intern to a higher rank and then starts treating their co-workers and new interns rudely.
Best Answer
tyrant (noun) - to refer to the person
tyrannical (adjective) - to describe a person's tendencies
No, I don't mean these words in the sense of a Mussolini or Stalin, but generally for a person who exercises power harshly over those to or for whom they are responsible, sometimes subordinates.
It's actually tricky to get good definitions of these words because it usually goes something like:
tyrant = One who is tyrannical
tyranny = Something tyrannical
tyrannical = Characteristic of a tyrant or tyranny.
So we have a bit of a loop here. However there are some definitions that are useful:
Of course these words don't describe people who are particularly susceptible to becoming tyrants once endowed with greater power or authority, but this is the closest I could get. I'd be interested in knowing if there's a term, maybe a psychological one, for a person who can easily let power go to their head, as you say.
Also, I know you're looking for a single word, but the idiom "drunk with power" contains within it the meaning that the person has become bossy after gaining authority or power.
One dictionary (Oxford Living Dictionaries) has an entry for "power-drunk", but no others do, so I wouldn't use it outside an informal context.