expression
not without its worth; not altogether hopeless; not to be undervalued
Used to say that something or someone has more value, ability, or potential than one might assume, often after a disappointing first impression. Commonly follows a noun marked with も.
彼のアイデアも捨てたものではない。
His idea is not without its worth, either.
この古いカメラも捨てたものではない。まだ十分使える。
This old camera isn't altogether hopeless. It's still perfectly usable.
The base verb meaning 'to throw away' or 'to discard'. The expression 捨てたものではない literally means 'it is not something thrown away', i.e., it still has value.
A similar expression meaning 'not to be made light of' or 'not to be underestimated'. 捨てたものではない focuses more on hidden worth, while 馬鹿にできない emphasizes that something should be taken seriously.
From 捨てる (to throw away) + た (past) + もの (thing) + ではない (is not). Literally 'it is not a discarded thing', implying that something still has value or potential.