Cram School Student
noun
Remember how 学生 is "student"? This plays off that. A cram school "student" is a student of a cram school, a cram school student.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
彼は塾生たちの中で一番記憶力が悪かった。
He has the worst memory out of all the cram school students.