Old student saw and followed orders (6)
I believe the answer is:
obeyed
'followed orders' is the definition.
(I've seen this before)
'old student saw' is the wordplay.
'old student' becomes 'ob' (I can't explain this - if you can you should give a lot more credence to this answer).
'saw' becomes 'eyed' (I've seen this before).
'ob'+'eyed'='OBEYED'
'and' acts as a link.
Can you help me to learn more?
(Other definitions for obeyed that I've seen before include "Did what one was told" , "Carried out someone's instructions" , "Complied with demands" , "See 8" , "Conformed" .)