The English idiom “keep your hair on” is something that an English speaker might say to ask someone to be calm, or avoid getting angry or emotional about something. It can also mean to wait for something patiently. This phrase is one of several similar idioms that English speakers use to either request, demand, or suggest patience, according to the contexts in which these phrases are used.
Some more formal synonyms for the phrase, “keep your hair on,” would include “don’t rush,” “be calm,” and “be patient.” In addition, there are several other English idioms that use the concept of “keeping something on” to refer to the idea of patience. Many of these are related to dress. For example, an English speaker might also tell someone to “keep your shirt on,” which has the same meaning.
Variations of these idioms also exist. For example, some English speakers might also tell someone else to “keep your pants on.” Other similar idioms with the same meaning include “hold your horses,” which creates a physical metaphor to the driver of a team of horses. A shorter idiom with the same meaning is the phrasal verb “hold on,” which is also commonly used.
Another idiom that relates to the concept of hair is “keep your wig on.” This is yet another phrase that means “be patient” or “don’t get angry.” Some newer English slang also uses the word “wig” in the same general context. In modern English, speakers might say “don’t flip your wig.” In addition, another phrasal verb, “wig out” has been created to refer to the process of becoming angry or impatient. English speakers might ask each other not to wig out, or describe one another as “wigging out” when they become overly angry or excited. Other synonymous phrasal verbs include “flip out” and “freak out.”
In general, many of these phrases are only used in informal situations. Many of them, including “keep your hair on,” can have a slightly insulting tone if used in the wrong way. Those who are on an easy footing as equals can usually use these phrases in communication with each other, but, for example, a subordinate would usually not say something like “keep your hair on” to a boss. A sales person would also avoid using these kinds of phrases to customers. These phrases often require an element of humor to be used effectively.