incumbent
adjective
definition 1: currently holding an office or position.
example: No one is running against the incumbent senator in this election.
definition 2: required or obligatory.
example: As your superior, it is incumbent upon me to warn you against improper use of this equipment.
definition 3: resting, leaning, or pressing on something.
noun
definition: one who currently holds a position or office.
example: The popular incumbent will be difficult to beat in the upcoming election.
Explanation and Etymology:
Incumbent meaning “currently holding an office or position” and its corresponding noun sense are the most frequent and important senses of this word to know. Adjective definition 3, “resting, leaning, or pressing on something,” is the closest to the earliest, Latin meaning of the word. The Latin verb incumbere means to lie down or lean on or against something. Contemporary use of incumbent, definition 3, seems limited to narrow, specialized contexts in botany and geology: inside the structure of a flower, the position of anthers and cotyledons are called “incumbent” when they rest on other flower parts; “incumbent rock strata” are supported by other strata.
More fruitful for your general vocabulary might be the ability to identify the family of words that contain this Latin verb root “cumb“: “recumbent,” as in the “recumbent bicycle” that allows the rider to lean back almost to the point of lying down and pedal. I saw a recumbent bicycle rider today, while attending some crew races on an inlet of Cayuga Lake. He was sporting a belly, easy to notice with him in his recumbent position, but he was also making nice progress at a good clip by pedaling from an almost prostrate position.
Succumb is built on the same Latin root and consists of the prefix sub- (under, below) plus the root cumb. Sub-, an assimilative prefix, adapts to the first letter of the root it precedes, which is why the prefix in succumb is suc-, not sub-. To succumb, then, is to lie down under some force. We always succumb to (under) something.
Coming back, now, to incumbent. How, given the etymology of the word in the Latin verb incumbere, can we connect the meaning illustrated in “the incumbent President” to the meaning of the Latin root? We welcome your thoughts on this.