又と無い

またとない
unique
matchless
unparalleled
never again

* * *

またとない【又と無い】

〔二つとない〕 unique; matchless; unequaled; unparalleled; stand unequaled; have no like [equal, parallel]; 〔二度とない〕 once-and-for-all.

●またとない品 a unique article; the only one of its kind

・またとない親友 a friend one couldn't find anywhere else

・またとない機会 a golden opportunity; the chance [opportunity] of a lifetime.

●こんな景色のよいところはまたとない. The place is unequaled [has no equal] in its scenic beauty.

・あれほどの天才はまたとないだろう. There will never be the likes of such a genius again.

・こんな機会はまたとない. We shall never have such a good opportunity again. | Such an opportunity knocks but once at the door.

・またとない好機をみすみす無駄にした. I let a once-in-a-lifetime opportunity slip between my fingers.