Real Dictionary

snag
countable noun: A snag is a small problem or disadvantage.
verb: If you snag part of your clothing on a sharp or rough object or if it snags, it gets caught on the object and tears.

snag in American English
a piece, part, or point that sticks out, esp. one that is sharp or rough, as the broken end of a tree limb
to catch, tear, etc. on a snag
to strike or become caught on a snag in water
intransitive verb: to become entangled with some obstacle or hindrance
noun: a tree or part of a tree held fast in the bottom of a river, lake, etc., and forming an impediment or danger to navigation
transitive verb: to run or catch up on a snag

snag in British English
noun: a difficulty or disadvantage
verb: to hinder or impede