This phone is still fully-functional despite being dropped several times.

fully-functional 是由副词 fully（完全地）和形容词 functional（功能的、可用的）组成的复合形容词。fully 来自形容词 full（完全的），functional 来自名词 function（功能）加上后缀 -al 变成形容词。fully-functional 合起来表示"功能完全正常的"。