persistent as in never-ceasing

• "the relentless beat of the drums"

Synonyms

• relentlessnot to be placated or appeased or moved by entreaty; never-ceasing
• unrelentingnot to be placated or appeased or moved by entreaty; punishingly harsh; never-ceasing

persistent as in continually recurring to the mind

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

Synonyms

• hauntingcontinually recurring to the mind; having a deeply disquieting or disturbing effect

persistent as in retained

• "not shed"
• "persistent leaves remain attached past maturity"
• "the persistent gills of fishes"

Synonyms

• lastingcontinuing or enduring without marked change in status or condition or place; existing for a long time; retained; lasting a long time without change

persistent as in stubbornly unyielding

• "dogged persistence"
• "dour determination"
• "the most vocal and pertinacious of all the critics"
• "a mind not gifted to discover truth but tenacious to hold it- T.S.Eliot"
• "men tenacious of opinion"

Synonyms

• doggedstubbornly unyielding
• dourstubbornly unyielding; harshly uninviting or formidable in manner or appearance; showing a brooding ill humor
• pertinaciousstubbornly unyielding
• tenaciousgood at remembering; stubbornly unyielding; sticking together
• unyieldingstubbornly unyielding; resistant to physical force or pressure