I'm marking some definitions as 'archaic' and some as 'obsolete'. From what I understand, veralten means for something to become outdated.

So I think the definitions could be marked up as:

• veraltet - obsolete / no longer in use (past participle)

• veraltend - archaic / becoming obsolete (present participle)

Is this correct? Can the words ever be used interchangeably? Are any other words preferred when trying say a definition is archaic or obsolete?