Synonyms for Antecedent (same or very similar meaning)
WordNet sense 1 (anything that precedes something similar in time):
forerunner
WordNet sense 2 (someone from whom you are descended (but usually more remote than a grandparent)):
ancestor, ascendant, ascendent, root
WordNet sense 3 (earlier in time):
anterior, prior
WordNet sense 4 (preceding in time or order):
preceding
From the ODE community, based on WordNet
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