I didn’t use the word “thwart” in The Grey House Trilogy. Here is a paragraph from That Which has No Name, where I do use the word:
Althea watched the interaction, intrigued. It was obvious that the Pastor thought well of the daughter. It was also obvious that she liked the man, as she kept looking at him from over her mother’s shoulder. But her mother was thwarting the girl’s every attempt to talk to the Pastor. It was amusing, and educational. Althea stood and smiled, her plan already formulating in her mind. She walked out of the church, into the nearby woods. If her plan was going to work, she would need to ditch her current host.