Hello momo, Yes both are adjectives, yet while someone is frustrated something is frustrating. The difference is: Frustrated: having failed in a disappointing manner or feeling disappointed for failing to accomplish an intended result. Frustrating: preventing the completion or the attainment of a desire or discouraging by keeping something from happening. Example: He is frustrated for having not passed the exam. His result is frustrating. When he didn't get the job , he felt very frustrated. Failing to get a desired post is very frustrating. I hope the difference is clear :)

From www.thefreedictionary frus·trate (frstrt) tr.verb. frus·trat·ed, frus·trat·ing, frus·trates 1. Meanings a. To prevent from accomplishing a purpose or fulfilling a desire; thwart: A persistent wind frustrated my attempt to rake the lawn. b. To cause feelings of discouragement or bafflement in. 2. To make ineffectual or invalid; nullify.

Hello Momo Both are adjectives but use "frustrating" for a thing like a job for example and "frustrated" for someone who feels that.