Strong's Concordance

heb

maw-sas'

"mâçaç"

מָסַס

1) to dissolve, melt
1a) (Qal) to waste away
1b) (Niphal)
1b1) to melt, vanish, drop off, melt away
1b2) to faint, grow fearful (fig.)
1b3) wasted, worthless (participle)
1c) (Hiphil) to cause to melt

a primitive root;

Englishman's Concordance

and the heart melteth and the knees