Become inflexible whenever shaven-headed authoritarian is around (6)
I believe the answer is:
ossify
'become inflexible' is the definition.
(I've seen this in another clue)
'shaven-headed authoritarian is around' is the wordplay.
'shaven' becomes 'if' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'headed' means to remove the first letter (head can mean to remove the top from something).
'authoritarian' becomes 'bossy' (I've seen this before).
'is around' means one lot of letters goes inside another.
'bossy' with its initial letter removed is 'ossy'.
'if' put within 'ossy' is 'OSSIFY'.
'whenever' is the link.
I am not very happy about this link. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for ossify that I've seen before include "Get hard" , "Turn to bone with age" , "Convert into bone" , "become inflexible" , "Make rigid" .)