1.
beautiful
Having qualities that give great pleasure to the senses or mind. A more literary and formal word for beauty compared to きれい.
美しい conjugates as an i-adjective: 美しくない (negative), 美しくて (te-form), 美しかった (past). This is more literary/formal than きれい (which is also used for 'clean'). 美しい has a deeper, more aesthetic connotation and is used in poetry and formal contexts.
Related: 美しさ (うつくしさ - beauty, noun).