The term 'not capable' can be described by three words: 'UNFITTED' (8 letters), 'INEPT' (5 letters) and 'UNABLE' (6 letters). UNFITTED means not suitable or appropriate for a particular purpose, while INEPT means lacking the ability or skill to do something. UNABLE is defined as not having the power, strength or resources to do something. All three words indicate an inability to do something, either due to lack of skill or resources.