"kos" is the slang Persian word for "vagina", and "khol" is the informal Persian for "eccentric"/"stupid"/"wacko". "kos-khol" /k(something between schwa and c:)skc:l/ is a person who is easily cheated or abused; is a freak who is completely unpredictable and is capable of doing any strange thing like flying a kite out of his/her ass, for instance; has completely no clue of what is going on. The English equivalents for "kos-khol" can be "a jackass", "a douche-bag", "a sucker", "a freak", or maybe a "dork"/"geek". Below I put a famous expression using "kos-khol" notion.
"mage koset khole/mage koset khol
Literally in English: "Is your vagina stupid/wacko?", only used by men means, "Are you out of your mind
Literally in English: "His/Her vagina is stupid.", only used by men means, "He/She is stupid/eccentric/...
nigash kon. Bejaye inke sandalisho bekeshe jolo dare Piano ro mikeshe tarafe khodesh."
English: "Look at the douche-bag
! Instead of moving the stool closer to the Piano, he is pushing the Piano closer to the stool."
"Agha, hamamoon kos-khol
shode boodima. Vas khatere peikas inkararo kardim. Harke bebine fek mikone ma gay im!!"
English: "Guys, we all totally went out of our minds
. The drinks caused all these things. Whoever sees these would think we're gay!!"
"Be oon dadashe kos-khol
etam salam beresoon."
English: "Say hello to that jackass
brother of yours too."