If something juts out, it sticks out above or beyond a surface. The northern end of the island juts out like a long, thin finger into the sea = protrude
If you jut a part of your body, especially your chin, or if it juts, you push it forward in an aggressive or determined way. His jaw jutted stubbornly forward; he would not be denied Gwen jutted her chin forward and did not answer the teacher Ken's jaw jutted with determination