Sentence:  “She's a <WSD>shitty</WSD> teacher, but Ault was in a bind.” But she hadn't been a <WSD>shitty</WSD> teacher when she'd been hired. She'd never taught before. And who was Aspeth to decide she was <WSD>shitty</WSD> now? She was still inexperienced. 
Meaning of the word marked with <WSD> tags:  Of low quality or standard; inferior; not up to par, or failing one's expectations