I'm looking for a single word for "lazy student". In my own language there is such a word that a teacher would use for a student who doesn't engage and doesn't care. In English, the word "slacker" is the best I could think of.
Slacker — Dictionary.com
a person who evades his or her duty or work
Good-for-nothing — TFD
A person of little worth or usefulness.
Couch potato — TFD
an idler who spends much time on a couch (usually watching television)
Couldn't find any word specifically tailored for students. Aren't most students like this anyway?
I think slacker works the best here:
a person who avoids work or effort
indolent Disinclined to exert oneself; habitually lazy.
from: Motivating Unmotivated Students http://www.ascd.org/ascd-express/vol5/504-reeves.aspx
"Many students think that they already know how to "play school"—keep your head down, don't bother the teachers, and do the minimum necessary. This path of least resistance is typified by the indolent student, who in turn is part of a society that is, in Robert Bork’s (1996) memorable phrase, "slouching toward Gomorrah. ..."
I'd suggest, dunce
: a dull-witted, stupid, or ignorant person.
[1520–30; after John Duns Scotus, whose writings were attacked by the humanists as foolish]
: a bad and lazy student.
Einstein, Churchill, and Hitler were dunces in school.
dunce cap or dunce's cap
A tall, cone-shaped hat formerly worn by slow or lazy students as a punishment in school (emphasis is mine.)
: Slang: Vulgar. a stupid, bumbling, foolish, or lazy person; jerk (emphasis is mine.)
Slang. One who shirks work or responsibility.
A bum is defined as a person who is lazy and does not work by choice.
A person who does no work; a lazy bum