To boil is a verb.
If you mean what is 0.333 ... recurring as a fraction then it is 1/3
I think you mean 'boil off' not 'off boil' and by this the recipe or person, etc, means to boil off something such as all of the oil in the foods so that it is not greasy when you get the result. ~Singer
If you mean recurring 2 then it is: 83/90 = 0.92222.....recurring
It means that 6 is a recurring decimal such as 0.16666...recurring 6
0.333333333... recurring. You can write it as 0.33, with a dot over the last 3, to mean "recurring".
Non-recurring means if you sign up for some kind of membership it means you will not be able to cancel it
Something is recurring if it happens on a regular or even irregular basis. A recurring nightmare is one that you've had in the past on more than one occasion.
boil, back
To boil, to be warm
Water and Boil Proof
"Boil brained" is not a common phrase in English. It may be a variation of "boil-brained," which could be interpreted to mean someone who is easily agitated or hot-headed. However, without more context it is difficult to determine the exact meaning.