unsuccessful

As adjectives the difference between unsuccessful and undefined

is that unsuccessful is failed, not successful while undefined is lacking a definition or value.

As adjectives the difference between unsuccessful and false

is that unsuccessful is failed, not successful while false is (label) one of two states of a boolean variable; logic.

As adjectives the difference between furtive and unsuccessful

is that furtive is stealthy while unsuccessful is failed, not successful.

Unsuccessful is a related term of unimportant.

As adjectives the difference between unsuccessful and unimportant

is that unsuccessful is failed, not successful while unimportant is petty; not important or noteworthy.

As adjectives the difference between unsuccessful and frustrated

is that unsuccessful is failed, not successful while frustrated is foiled, stopped, disappointed.

As a verb frustrated is

(frustrate).

As an adjective unsuccessful

is failed, not successful.

As a noun unsuccess is

a lack of success.

As adjectives the difference between unsuccessful and eccentric

is that unsuccessful is failed, not successful while eccentric is not at or in the centre; away from the centre.

As a noun eccentric is

one who does not behave like others.

As an adverb vainly

is in a vain manner; to no avail.

As an adjective unsuccessful is

failed, not successful.

As adjectives the difference between unsuccessful and failable

is that unsuccessful is failed, not successful while failable is capable of failing or becoming exhausted.

As a verb failed

is (fail).

As an adjective unsuccessful is

failed, not successful.