It is "racking one's brain".
One definition of the word racking is "To cause great physical or mental suffering, e.g. Pain racked his entire body."
To "rack one's brain" is idiomatic, but has the same general implication of stress.
Wracking
The adjective is spelled "nerve-wracking" (but also seen as nerve-racking).It is either from the variant wrack meaning to wreck, or rack as in the torture rack, which is seen in the idiom to rack one's brain (to stretch or exert).
"Racking his brain" means that he was thinking really hard to figure something out. For example, "He was sitting in a corner racking his brain over why his girlfriend broke up with him." This means that the man was trying really hard to figure out why his girlfriend broke up with him.
idiom but im not sure
A synonym for extremely difficult question can be exceptionally tricky problem requiring an answer.
maintain explain train brain drain main pain rain vain
The adjective is spelled "nerve-wracking" (but also seen as nerve-racking).It is either from the variant wrack meaning to wreck, or rack as in the torture rack, which is seen in the idiom to rack one's brain (to stretch or exert).
It is technically either.But the word form used in the US vernacular is to "wrack" one's brain (or brains). The word wrack is a variant of "wreck", to ruin or destroy.This causes the dichotomy in "nerve-racking" and "nerve-wracking" : the US use tends toward the wracking as in wrecking, but racking can apply to torture as in stretching on a rack.(see related question)
It can be when it applies to a running horse (a racking pace), where rack is a gait.Otherwise, racking (the present participle of the verb to rack) is a verb form or a noun.*note that the homophone wracking is likely the proper word in wracking pain
"Racking his brain" means that he was thinking really hard to figure something out. For example, "He was sitting in a corner racking his brain over why his girlfriend broke up with him." This means that the man was trying really hard to figure out why his girlfriend broke up with him.
The phrase "racking his brain" means to think very hard or make a great effort to remember or solve a problem. It implies a person is putting a lot of mental energy into trying to figure something out.
to want to do something; a wanting to entertain oneself
It means, "Wracking my brain, trying to talk to you."
it is spelled kaut. See? you no have brain like me.
Oh yes, nerve wracking is two words.
idiom but im not sure
In teenage slang, "racking" usually means stealing or shoplifting items from a store without paying for them. It is considered illegal and unethical behavior.
A synonym for extremely difficult question can be exceptionally tricky problem requiring an answer.