Chemah in Hebrew, usually translated as curd. It is something that can be eaten alone; see Isaiah 7:15, 7:22; cf. Proverbs 30:33. Others interpret it to denote a kind of leben or yoghurt. According to Rashi, the word chemah denotes cream. (cf. Targum and Judges 5:25). The Septuagint, on the other hand, translates it as butter. Indeed, in Middle Eastern lands, it was the custom to eat butter alone.
So we see a pretty wide range of dairy products as possible translations. Klein says that the word chemah is related to the Arabic hami'a - "it was turbid". According to this site:
As the word chemah, here translated butter, signifies disturbed, agitated, probable that buttermilk is intended. The Arabs form their buttermilk by agitating the milk in a leathery bag
This fits in well with the parallel given in Mishlei 30:33 -
כִּי מִיץ חָלָב, יוֹצִיא חֶמְאָה-- וּמִיץ-אַף, יוֹצִיא דָם;וּמִיץ אַפַּיִם, יוֹצִיא רִיב.
"'The churning of milk brings forth butter, the wringing of the nose brings forth blood, and the forcing of anger brings forth strife"
The connection of "turbid", "agitated", and "anger" may give us a clue to the origin of the word. It may be related to the Hebrew chema חמה - "anger". (There is also likely a connection between both חמה and חמאה and the word for heat - חום chom. When one is angry, he is "heated up". But it does not seem to be that chemah חמאה directly derives from "heat".)
This gives an etymological connection to a strange association I have every year at Purim. When I hear Ester 3:5 -- וַיִּמָּלֵא הָמָן, חֵמָה, I can't help thinking of Haman (maybe hamantaschen?) filled with butter....
The Hebrew word for compliment - מחמאה machma'ah, derives from chemah. However, there's more to it than just a parallel to the English "butter up". As this article explains, the word machma'ah was formed from a misreading of Tehillim 55:22 -