兼
ケン, か.ねる, か.ねる, かね

concurrently, and

JLPT1 G7 S10 F1164

The relevant seal inscription form shows two ears of grain + a hand → storehouse encompassing grain that has been gathered then stored/put away → *combine*; *unite*; *serve/perform concurrently*; *simultaneous*. *Unable to do* is a borrowed meaning. In derivative characters, 兼 may also appear in the form seen for example in 嗛, 歉 or 賺.

[Full Kanji Etymology List]