Yes, " Unable to " is very different to that of " Not able to ".
Grammatically any failure / fall of action is denoted by " Un+Able ". When people speak, they colloquially tend to get the " Not " as the strong notation of affirming the failure in action, deriving " Not able ". As a layman both means the same, but per grammar the fail of action is mentioned " Unable to ".
Regards,
Subu
Some words with the suffix able include: unable, believable, and imaginable.
Some words that end in -able are stoppable, table, fable, and unable. Some additional words are lockable, knowable, passable, sortable, and workable.
Suggestions: It is able It has the power to It is within its ability to It is not unable (haha)
unable mis able
Unable to meet with you!
Unable, incapable
Nothing is different between 'can' and 'be able to'. They are simply two different words with the same meaning of 'i can do this'. Hope this helps.
unable
agree-ablelove-ableExcite-able
The prefix of "able" is "un-".
How to able your iMessage
Unable