What term refers to someone or something that is clumsy or awkward?

The term "ungainly" specifically describes someone or something that is clumsy or awkward in movement or appearance. This word captures the essence of being lacking in grace or coordination, often leading to a sense of awkwardness in one's physical actions or demeanor.

In contrast, "graceful" denotes elegance and fluidity, which is the opposite of clumsiness. "Brittle" refers to something that is fragile or easily broken, not aligning with the idea of clumsiness. "Supple," meanwhile, suggests flexibility and ease of movement, which also does not convey awkwardness.

Using "ungainly" accurately addresses the question about clumsiness, making it the appropriate choice.