adj. unyielding
adv. unyieldingly
n. unyieldingness
v. to not yield; to make or become unyielding

Orin pruzaan dwiin aal kreh ahrk kren, nuz Slen do vahzah muz los sindugahvon.
Even the best steel may bend and break, but the Flesh of a true man is unyielding.
(Word Wall for Slen, Ice Form)

From gahvon ‘to yield’. Exact derivation is unknown, but du- may be a negative prefix and si(n)- may also appear in sizaan ‘lost’.

Misspelled as sindungahvon in the PrimaGames.com list.