Wormy means full of worms, or having worms in it — wormy apples, wormy meat, wormy soil. It is the plain adjective you make from 'worm' by adding -y, the same way rain becomes rainy and dirt becomes dirty. It has two slightly different jobs. Most often it is a complaint: a wormy apple is one you would not want to eat. But with soil, a gardener may say 'nice wormy soil' as praise, because earthworms mean the ground is healthy. So the feeling depends on where the worms are. It can also mean simply worm-like — long, thin, and wriggling. A wormy line of handwriting, a wormy squiggle on a page. And, more rarely, it describes a person as weak, cringing, or not to be trusted, the same insult carried by calling someone 'a worm'. That last use is old-fashioned and you meet it mostly in books. 'Wormy' is an everyday, spoken word, not a formal one; in careful writing about food or timber you would more often see 'infested' or 'worm-eaten'.