1
to challenge to (a fight, game, etc.);to throw down the gauntlet;to contend for
そのインディアンの群れは、ほんのちょっとでも怒らすと戦いを挑もうとした。
The band of Indians were ready to go on the warpath at the slightest provocation.
2
to tackle (e.g. a problem);to attempt;to go after (a prize, record, etc.)
3
to pressure (someone) for sex;to make advances to
昨夜は結美のほうから挑んできたんだ。
Last night it was Yumi who pushed for sex.