saplesti

1. (saplesti se) to trip; to stumble
   Sapleo sam se o kabl i pao. — I tripped over a cable and fell.
   Saplela se na stepenicama i uganula nogu. — She tripped on the stairs and sprained her ankle.
2. (+ acc.) to trip someone
   Namerno me je sapleo na času fizičkog. — He tripped me on purpose in PE class.
3. (saplesti se, figurative) to stumble; to falter
   Sapleo se već na prvom pitanju. — He stumbled on the very first question.
   Glumica se saplela u tekstu, ali je brzo nastavila. — The actress stumbled over her lines but quickly carried on.

The thing one trips over usually takes o + accusative: saplesti se o kamen.