- (literally) A dense thicket of thorny plants; ground made impassible by the impenetrable overgrowth of prickly vegetation.
- -I'm sick of going over and through every obstacle on the hill.
- -"Every obstacle"?!? We missed the briar patch, didn't we?
- (figuratively) An intellectual or philosophical issue abounding with seemingly unresolvable problems; a theoretical quandary or impasse.