persistent

英[pə'sɪst(ə)nt] 美[pə'zɪstənt]

1. never-ceasing;

"the relentless beat of the drums"

2. continually recurring to the mind;

"haunting memories"

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

3. retained; not shed;

"persistent leaves remain attached past maturity"

"the persistent gills of fishes"