Gloss over title claimed by the Spanish (6)
I believe the answer is:
enamel
'gloss over' is the definition.
(to coat with enamel)
'title claimed by the spanish' is the wordplay.
'title' becomes 'name' (I've seen this before).
'claimed by' means one lot of letters goes inside another.
'the spanish' becomes 'el' ('the' in Spanish).
'name' going within 'el' is 'ENAMEL'.
(Other definitions for enamel that I've seen before include "Hard, glossy protective coating" , "Decorative or protective covering on metal or glass." , "hard stuff" , "art form" , "protective coat" .)