Ungainly is the opposite of graceful, convenient, or easy. A clumsy dancer boogies in an ungainly or awkward fashion.
Though you see gain in ungainly, the word does not have to do with growing, or getting ahead. Ungainly comes from an Old Norse word meaning not convenient or, in other words, awkward. If you want to impress your gym teacher or sports coach, first appear ungainly and then surprise him with your great athletic ability. Applying to college can be an ungainly process without an advisor to help.