I think you already know the answer to this question, because otherwise you wouldn't ask if it's appropriate or not.
Maybe you're hoping someone here would tell you that it's okay to lie during an interview.

Imagine if you lied and you got the job, and the first thing you're asked to do on the job has to do with the very thing you lied to them about.

Or even worse, imagine if during the interview you lied and the interviewer happens to be an expert in that field and starts asking you detailed questions on that subject (this happens more often than some may think).

So here's the answer - NO. If you don't know something or don't possess a certain skill, just be honest and say so. Interviewers are almost always experienced people and they'll detect your lies one way or another.