unsuccessful

As adjectives the difference between unfruitful and unsuccessful

is that unfruitful is of or pertaining to not bearing fruit (usually figuratively) while unsuccessful is failed, not successful.

As adjectives the difference between satisfactory and unsuccessful

is that satisfactory is done to satisfaction; adequate or sufficient while unsuccessful is failed, not successful.

As adjectives the difference between unsuccessful and capable

is that unsuccessful is failed, not successful while capable is able and efficient; having the ability needed for a specific task; having the disposition to do something; permitting or being susceptible to something.

As adjectives the difference between unsatisfactory and unsuccessful

is that unsatisfactory is inadequate, substandard or not satisfactory while unsuccessful is failed, not successful.

As a noun taxonomy

is the science or the technique used to make a classification.

As an adjective unsuccessful is

failed, not successful.

As adjectives the difference between unsuccessful and successless

is that unsuccessful is failed, not successful while successless is without success; unsuccessful.