chafifa

Chafifa חפיפה can mean both "shampooing" and "overlapping" (often used when two people are overlapping at a job, and one needs to train another). Is there a connection between these two Hebrew homonyms?

From every reliable source I've seen, they come from two homographic, but distinct, roots: חפף.

Let's look first at the root that gives us "overlapping." In this case, חפף means "to surround, cover." By extension, it can also mean "to protect" or "to be congruent" (this is the sense that leads to "overlap.") A related root is חפה.

From this root we get a number of familiar words:

• chupah חופה - the wedding canopy (which covers the bride and groom)
• chof חוף - "coast" (which surrounds the land)
• chipui  חיפוי - covering (or suppressive) fire, used in a military context to prevent an enemy from attacking

The other meaning of חפף is "to rub." From there developed the sense of "to cleanse the head by rubbing", i.e. shampooing.  This type of cleanliness is extended to a general sense of being clean, pure - and so it also gives us the word חף chaf - "innocent", often used in the phrase chaf m'pesha חף מפשע - "innocent of crime."

According to some sources, the word yachef יחף - "barefoot" also derives from a cognate of this root. The idea is that removing shoes is like rubbing or peeling them off. 

All of the roots above have Arabic cognates as well. Ruvik Rosenthal points out that there are two more Arabic roots, which have similar spellings, but aren't cognate with the ones we've discussed before. They gave us two Hebrew slang words (and I haven't been able to find any earlier Hebrew cognates).

One is the word chafif חפיף. In Arabic it means "light", "nimble" or "agile." When it entered Hebrew it came to mean "lightweight", "wishy-washy" or "sloppy", and a chafifnik is a "slacker." 

The other word is a verb - התחפף hitchafef. When talking in the past tense it means "took off", and in the imperative, it means "scram" or "get lost." While Rosenthal says it is a fourth, distinct root, this Wiktionary entry says it comes from the same root as chafif - something light as air can easily "disappear", "go away."