cái​dà​nán​yòng

useless due to size

Senses

材大难用/ 材大難用 cái​dà​nán​yòng useless due to size

Literally referring to a tree with a trunk so swollen or branches so gnarled that it does not fit standard tools (from 庄子 zhuāng​zǐ)

材大难用/ 材大難用 cái​dà​nán​yòng great talent is hard to employ

Metaphorically used to describe a person with great talent who cannot find a suitable position or whose abilities are underutilized

References

variant 才大难用/才大難用 材大难用/材大難用