Importunate (adjective)

1. Persistently demanding or asking for something; persistently urging or pressing for something.
2. Annoyingly persistent; persistently bothersome.

Origin:

Late middle english: from latin importunus "unseasonable, troublesome", from in- "not" + portus "harbor, haven".

Examples:

1. The importunate salesperson would not take no for an answer.
2. His importunate requests for a raise were ignored by his boss.
3. The importunate phone calls from the charity were a nuisance.
4. She found his importunate nature endearing, unlike others.
5. The importunate demands from the client made it hard for the company to deliver the project on time.