to make persistent demands of (somebody)
to be troublesomely persistent in asking for (something)
to solicit (somebody) for purposes of prostitution
to beg, urge, or solicit with troublesome persistence
importuner noun
importunity /-ʹtyoohniti/ noun
[early French importuner from medieval Latin importunare, from Latin importunus unfit, troublesome, from in-1 + -portunus as in opportunus: see opportune]