大材小用

using a talented person in an insignificant position (idiom) / a sledgehammer to crack a nut

see 大夫[dai4 fu5]

big; large; great / older (than another person) / eldest (as in 大姐[da4 jie3]) / greatly; freely; fully / (dialect) father / (dialect) uncle (father's brother)

material / timber / ability / aptitude / a capable individual / coffin (old)

small / tiny / few / young

to use / to employ / to have to / to eat or drink / expense or outlay / usefulness / hence / therefore