unable vs ineffective

unable and ineffective both are adjectives.

Word	Noun	Adjective	Verb	Adverb
unable	No	Yes	No	No
ineffective	No	Yes	No	No

As adjectives, unable and ineffective are synonyms defined as:

Other synonyms of unable include ineffectual.

unable (adjective)	ineffective (adjective)
(usually followed by `to') not having the necessary means or skill or know-how	not producing an intended effect
lacking in power or forcefulness	lacking in power or forcefulness
(usually followed by `to') lacking necessary physical or mental ability	lacking the ability or skill to perform effectively; inadequate