When you're devoted to or in awe of something, you're worshipful. Do you adore and admire your older cousin? You could say that your love for her is worshipful.
When you're worshipful, you worship someone or something. Both words are commonly used in a religious context, to talk about adoration and reverence for a deity: "For Buddhists, worshipful meditation is an important practice." These days, worship and worshipful are also frequently used in non-religious ways as well. If you finally get to see your favorite band perform, you might end the night with worshipful tears streaming down your face, so intense is your admiration for their music.