What's the prefix of not efficient
super-
"Possibility" doesn't have a prefix. You could add the prefix im- to it to make the word impossibility.
The current prefix is ex-. You could add the prefix in- to it to make the word inexcusable.
The current prefix is im-. You could add the prefix un- to it to make the word unimportant.
What's the prefix of not efficient
The "w" prefix can stand for "with," in the context of being efficient when working with or using something.
super-
The prefix you can add to charge is "re-," as in "recharge."
The adding a prefix to the word "add" would result in the word "postadd".
Add (something) at the beginning as a prefix or introduction.
In the word "inform", in- is a prefix. You could add the prefix mis- to it to get misinform.
"Im" is a common prefix in itself, you don't add a prefix to a prefix.
The correct prefix to add to "fashionable" is "un-", resulting in "unfashionable."
To add a prefix to the word "definitely," you could use "in-" to form "indefinitely."
dinutrition
You could add the prefix af- to it to make the word affluent.