The first mobile phones were heavy and clumsy to use, but nowadays they are much easier to handle.
第一代手機用起來很笨重,而現在的手機就輕便多了。
My attempts to apologize were very clumsy (= not said well).
我想道歉,卻拙嘴笨舌的。
That's the third glass you've smashed this week - you're so clumsy!
這已經是你這個星期打破的第三隻杯子了——真是太笨了!