Not fully made use of

Wiktionary Word definitions in Wiktionary
a. employed in a job for which one is overqualified; or employed in a job that does not pay as much as one wants or expects.

WordNet Word definitions in WordNet
adj. employed only part-time when one needs full-time employment or not making full use of your skills; "migrants are likely to be poor and underemployed"; "able people are kept underemployed"

Wikipedia Word definitions in Wikipedia
Underemployed may refer to: A person subject to underemployment . Underemployed (TV series) , a comedy-drama television series that airs on MTV.

Longman Dictionary of Contemporary English Word definitions in Longman Dictionary of Contemporary English
adjective EXAMPLES FROM CORPUS ▪ Although he might well spend his days in one place, obsessively devoted to music-making, he would always be morally underemployed . ▪ Its wealth was largely non-industrial and it contained an enormous pool of underemployed ...