不成材

worthless / good-for-nothing

no; not so / (bound form) not; un-

won't do / unable to / (at the end of a rhetorical question) can that be?

surname Cheng

to succeed / to finish / to complete / to accomplish / to become / to turn into / to be all right / OK! / one tenth

to make sth of oneself / to become a person who is worthy of respect / (of a tree) to grow to full size / to become useful for timber

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