cognitive refers to
thought. Thought in humans, animals, anything meeting the definition(whichever you're using) of
thinking.
metacognitive refers to
observing your own thought. For instance
displacing myself to question whether I'm really in love. I consider my own thoughts. This second "level" of thought is referred to as being
metacognitive thought, or
metacognitive processing.
Describes a state of
metacognition.