Attacks blocked by foremost of titanium headwear (7)
I believe the answer is:
stetson
'headwear' is the definition.
I can't tell whether this definition defines the answer.
'attacks blocked by foremost of titanium' is the wordplay.
'attacks' becomes 'sets on' ('set on' can be a synonym of 'attack').
'blocked by' means one lot of letters goes inside another (upper walls off glass inside formal).
'foremost of' says to take the initial letters.
The initial letter of 'titanium' is 't'.
'setson' placed around 't' is 'STETSON'.
Can you help me to learn more?
(Other definitions for stetson that I've seen before include "Hat for country-and-western singers, Texan oil magnates, etc." , "Hat with wide brim and high crown, maybe a cowboy's" , "A wide-brimmed cowboy hat" , "Capital investment" , "St Neots (anag.)" .)