Ḥāmēẓ vs. ḥummuṣ.

 Yes! Despite their appearing to be spelled identically and both referring to food, Hebrew חמץ (ḥāmēẓ, in Yiddish xomeʦ) unleavened bread, and Arabic حمص (ḥummuṣ) chickpeas are from two different roots. While it is true that the Hebrew letter צ (ṣāddî) corresponds to the Arabic letter ص (ṣâd), it also sometimes corresponds to the Arabic letter ض (ḍâd) which is the case here. חמץ comes from the ḥ-m-ḍ (חמץ׳، حمض) root meaning sour, and is thus cognate with the Arabic حامض (ḥâmiḍ) sour, حمض (ḥamḍ) “a bitter plant, sorrel” and حميض (ḥamîḍ) “tract of land abounding in bitter herbs.” (The quotes are from F. Steingass, A Learner’s Arabic-English Dictionary [Beirut: Librairie du Liban, 1989]. Thanks also to John Wortabet and Harvey Porter, Hippocrene Standard Dictionary: Arabic-English English-Arabic [New York: Hippocrene Books, 2000].)

 Dave Curwin (DLC) suspected as much in his Web log article “chametz,” Balashon - Hebrew Language Detective, 12 April 2006. A comment on that article nearly a year later by Justin a.k.a. The Mad Latinist, 7 April 2007, confirms it. However, in his article “Chickpeas,” The Jewish Daily Forward, 21 October 2005, Philologos appears to be forcing a connection between ḥāmēẓ and ḥummuṣ where it doesn’t actually exist: “The reason for this, as you will know if you ever have left chickpeas or hummus paste in the refrigerator too long, is that both have a tendency to sour quickly.”