Mummy, theres mud on my trousers, says a five-year-old boy in alarm. I need to go home and change.



Ah, hes my little istenis, the mother explains to her friends at the playground. You might overhear such a conversation in certain Jewish communities.



Istenis is a Talmudic term deriving from the Greek for squeamish or weak and is a category in Jewish law.



For example, Jewish law forbids a mourner to bathe during the shivah period. When the students of Rabban Gamliel saw that he had bathed the day after his wife had passed away, they confronted him. He replied, I am different than other people; I am istenis.



Indeed, the halachah exempts someone who is so discomfited by the notion of not washing for seven days from this prohibition (Berachot 19a).



Commentators explain than an istenis who takes advantage of his/her exemption does not derive any pleasure from bathing, which is the reason for the prohibition in the first place.



Nowadays, istenis is used colloquially to refer to someone who is very particular about cleanliness and order.



Many centuries after the sages of the Talmud granted legitimacy and therefore lenience to people suffering from hypersensitivity, Freud, the great sage of psychoanalysis, diagnosed the condition Obsessive Compulsive Disorder, arguably an extreme form of istenisiut.