(not) at all; completely; utterly
Used with a negative predicate to mean 'not at all' or 'completely not'. Emphatic negative.
I don't understand what he's saying at all.
That movie wasn't interesting at all.
Rare affirmative use meaning 'very' or 'extremely'. Mostly found in older or dialectal speech; modern standard Japanese prefers とても or すごく.
I hear this area used to be very lively.
I have absolutely no idea what this equation means.
His plan was no good at all.
With conditions like that, it's completely out of the question.
まったく is a neutral, widely used way to say 'completely (not)', whereas てんで sounds more blunt and casual.
さっぱり with a negative also means 'not at all', but it leans toward describing a lack of feeling or result, while てんで is a general emphatic negator.
Kana-only adverb; no kanji form is used.
The origin is uncertain. It may be a sound-symbolic (mimetic) formation, but no clear derivation is known.