闘
トウ, たたか.う, あらそ.う, と
fight, war
JLPT1 G7 S18 F751
鬪 is a variant of 鬭 with the same meanings (*fight*; *battle*; *contend* → *strive*). Whether in error or as a simplification, 鬪 replaces 斲 with a variant of 尌 (set/stand in place) as described in 樹.
[Full Kanji Etymology List]