Unsuccessful
Part of speech: adjective
Definition: Failed, not successful.
Example sentence: Dad was a retired chemist who, in his 60s, fathered and fed me and my two sisters while Mum worked as a secretary. He made us curries, Chinese meals and strange concoctions. He was often unsuccessful.
Unfruitful
Part of speech: adjective
Definition: Of or pertaining to not bearing fruit (usually figuratively).