Should I accept a job offer while waiting for another?

No, you should not accept a job offer while waiting for another, at least not right away. Be honest with the hiring manager and ask for as much time as possible to consider the offer. If the other job doesn't get back to you within that time, then you will have to make a choice whether to reject your first offer and wait, or accept the first offer and remove yourself from consideration from the other job.

Technically you can accept the first offer and then back out if the other job gets back to you. However, this is not professional and can hurt your reputation moving forward.