Ahead and Pre-existent

Ahead adjective - Having the leading position or higher score in a contest.

Pre-existent and ahead are semantically related In some cases you can replace phrase "Pre-existent" with "Ahead", this terms are similar.

Pre-existent adjective - Existing previously or before something.

Ahead and pre-existent are semantically related in earlier topic. Sometimes you can use "Ahead" instead an adjective phrase "Pre-existent".