1. never-ceasing

Similar word(s): continual, relentless, unrelenting

2. continually recurring to the mind

Similar word(s): unforgettable, haunting

3. retained; not shed

- persistent leaves remain attached past maturity

- the persistent gills of fishes

Similar word(s): lasting

4. stubbornly unyielding

- dogged persistence

Similar word(s): obstinate, stubborn, unregenerate, dogged, dour, pertinacious, tenacious, unyielding

Sentences with persistent as an adjective:

- She has had a persistent cough for weeks.

- There was a persistent knocking on the door.

- There have been persistent rumours for years.

- Pine cones have persistent scales.

- Once written to a disk file the data becomes persistent and it will still be there tomorrow when we run the next program.

- This way transient value becomes persistent.