[smell, noise, rain] persistant (e)
→ a persistent smell of rancid fat
→ the persistent noise of traffic
→ puddles caused by the persistent rain
[problem] persistant (e)
→ Inflation has been a persistent problem since World War II.
[pain, headache, cough] persistant, tenace
→ His cough grew more persistent.
[failure] persistant (e)