studying very hard; cramming intensely
Describes an intense, often short-term burst of studying, like cramming for an exam. Can be used as a noun or with する.
I have to study like crazy before the exam to pass.
After intense studying, he got into a top university.
Compound of 猛 (もう, 'fierce, intense') and 勉強 (べんきょう, 'study'). The prefix 猛 is used in similar compounds like 猛練習 (intense practice) and 猛暑 (intense heat).