One expects head to wear inferior underwear (7)
I believe the answer is:
panties
'underwear' is the definition.
(I know that panties is a type of lingerie)
'one expects head to wear' is the wordplay.
'one expects head' becomes 's' (I am not sure about this - if you are sure you should believe this answer much more).
'to' says to put letters next to each other (I've seen this in other clues).
'wear' becomes 'pantie' (pantie is a kind of wear).
's' put after 'pantie' is 'PANTIES'.
'inferior' acts as a link.
This may not be correct. It may be part of another bit of the clue.
Can you help me to learn more?
(Another definition for panties that I've seen is " Clothes".)