PERPETUITY

[noun] [U] [formal]The council wants the footpaths on the estate to become legal rights of way, which would give the public the right to use them in perpetuity (= for ever). perplex [verb] [T] - to confuse and worry (someone) slightly by being difficult to understand or solveThe disease, which affects young children of both sexes, has continued to perplex doctors and public health workers.