Today's word is "shitsukoi (persistent; obstinate; importunate; troublesome; heavy; gaudy)". "Shitsukoi" is usually written in hiragana.
* Seerusuman ga shitsukokute komatta. セールスマンがしつこくて困った。 --- The salesman was so persistent that I didn't know what to do.
* Itsumademo shitsukoku iuna. いつまでもしつこく言うな。 --- Don't keep after me like that!