Girl and boy forming a sort of line (6)
I believe the answer is:
dotted
'line' is the definition.
(thesaurus)
'girl and boy' is the wordplay.
'girl' becomes 'dot' ().
'and' means one lot of letters go next to another.
'boy' becomes 'Ted' (short for Edward or Theodore).
'dot'+'ted'='DOTTED'
'forming a sort of' acts as a link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for dotted that I've seen before include "Covered with spots" , "Sparsely laid out" , "Scattered" , "I may be" , "Sign on this line to authorise" .)