WordNet sense 1 (a period of time spent in military service):

enlistment, tour, duty tour, term of enlistment, tour of duty

WordNet sense 2 (the state of inactivity following an interruption):

arrest, check, halt, stay, stop, stoppage

WordNet sense 3 (an unforeseen obstacle):

rub, snag, hang-up

WordNet sense 4 (any obstruction that impedes or is burdensome):

encumbrance, hindrance, interference, preventative, preventive, incumbrance, hinderance

WordNet sense 5 (travel by getting free rides from motorists):

hitchhike, thumb

WordNet sense 6 (walk impeded by some physical limitation or injury):

gimp, hobble, limp

WordNet sense 7 (jump vertically, with legs stiff and back arched):

jerk

WordNet sense 8 (to hook or entangle):

catch