IPA: /ˌæntɪˈsɛsər/
KK: /æntɪˈsɛsər/
A person or thing that comes before another in time or position.
The antecessor of the current president was known for his strong leadership.
Antecessor is formed from "ante-" (meaning before) and "cedere" (meaning to go or yield). The word refers to someone who goes before or precedes another, often in a position or role.
Think of someone who 'goes before' ('ante-') another person — that's why an antecessor is someone who precedes.