die hard

die hard (third-person singular simple present dies hard, present participle dying hard, simple past and past participle died hard)

1. To die only after a desperate struggle for life. (of a living being)
2. To be slow in changing or disappearing. (of a custom, idea etc)
   • 1907, Ronald M. Burrows, The Discoveries In Crete, page 99:

     Already, however, in this earliest phase, new types cease to be invented; technical skill lingers on and dies hard, but inspiration has gone.

   • 1960 December, “The Glasgow Suburban Electrification is opened”, in Trains Illustrated, page 715:

     Another incentive to Glaswegians to make full use of their new facilities is that road-rail competition has died hard in this area and the prevailing fare levels, even though rail rates were recently increased, are somewhat low by standards elsewhere in Britain—[...].

• you can't teach an old dog new tricks

• dihedra