Slow moving bus to Spain (6)
I believe the answer is:
obtuse
'slow' is the definition.
(I know that slow can be written as obtuse)
'moving bus to spain' is the wordplay.
'moving' indicates an anagram (letters are moved around).
'spain' becomes 'e' (abbreviation for Espana).
'bus'+'to'='busto'
'busto' anagrammed gives 'obtus'.
'obtus'+'e'='OBTUSE'
(Other definitions for obtuse that I've seen before include "Slow-witted; type of angle" , "Blunt, not sharp or pointed" , "Orchestra; stripe" , "Dull, non-perceptive" , "Slow, dull" .)