One might pick this rugby forward (4)
I believe the answer is:
lock
'rugby forward' is the definition.
(lock is an example)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for lock that I've seen before include "element in pack" , "Stop moving" , "Fastening device" , "Tress of hair" , "Strand of hair" .)