Would-be (adjective)

1. Intending to be or to do something, but not yet having succeeded.
2. Intending or wishing to be or do something in the future.

Origin:

Compound of would and be, dating back to 1850–55.

Examples:

1. He was a would-be writer, always working on his novel.
2. She was a would-be actress, always performing for anyone who would watch.
3. The would-be thief was caught before he could steal anything.
4. The would-be murderer was stopped before he could carry out his plan.
5. The would-be champion never gave up and eventually won the competition.