šepati

1. to limp
   Posle utakmice je šepao na levu nogu. — After the match he was limping on his left leg.
   Pas šepa, verovatno se povredio. — The dog is limping, it probably got hurt.
2. (of work, plans, skills) to be weak; to fall short
   Organizacija festivala ove godine malo šepa. — The festival's organisation is a bit shaky this year.
   Matematika mu šepa, ali je dobar u jezicima. — He's weak at maths, but good at languages.

The bad leg is given with na + accusative: šepati na desnu nogu.