PERSISTENT

[adjective]Something that is persistent lasts for a long time or is difficult to get rid of.a persistent smell/skin rashpersistent debts/difficultiesSymptoms of the illness include a high temperature and a persistent dry cough.There have been persistent rumours that the managing director might take early retirement.Someone who is persistent continues doing something or tries to do something in a determined but often unreasonable way.Be persistent - don't give up.He has been a persistent critic of the president.She is a persistent offender and has been arrested five times this year for shoplifting.