The word "knaggy" refers to something that is rough and hard, like a piece of wood with rough edges or knots. Some synonyms for knaggy include "gnarled," "knotty," "rough-textured," "bumpy," "lumpy," and "rugged." These words all describe something that is not smooth or polished, but rather has a rough or uneven surface. Other synonyms might include "coarse," "gritty," "rocky," and "jagged." Whether you're describing a piece of wood, a rock, or even a person's personality, using words like these can help paint a clear and vivid picture for your readers or listeners.