Answer: an idiom
Step-by-step explanation:
In the sentence, "looked like a million dollars" is an idiom. An idiom is referred to as a term through which the meaning cannot be gotten literally from the words that it is made from.
An idiom is a group of words which has a meaning that's completely different from the meanings of the word on its own.
An example is saying someone has a cold feet. It doesn't mean that the feet of the person is cold but rather, it means that the perosn is nervous.