Junior boys apt to get lit up? (4)

I believe the answer is:

fags

I'm a little stuck... Click here to teach me more about this clue!

'junior boys' is the definition.
The answer and definition can be both people as well as being plural nouns.
Maybe there's a link between them I don't understand?

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for fags that I've seen before include "Does public school chores" , "Toils for slangy cigarettes" .)

I've seen this clue in the Evening Standard.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.