persistent

adjective

1. 1

   never-ceasing

   the relentless beat of the drums

2. 2

   continually recurring to the mind

   haunting memories

   the cathedral organ and the distant voices have a haunting beauty"- Claudia Cassidy

3. 3

   retained; not shed

   persistent leaves remain attached past maturity

   the persistent gills of fishes

4. 4

   stubbornly unyielding

   dogged persistence

   dour determination