Resinous substance the Spanish give out endlessly (5)
I believe the answer is:
elemi
'resinous substance' is the definition.
(elemi is a resin)
'the spanish give out endlessly' is the wordplay.
'the spanish' becomes 'el' ('the' in Spanish).
'give out' becomes 'emit' (synonyms).
'endlessly' means to remove the last letter.
'emit' with its last letter removed is 'emi'.
'el'+'emi'='ELEMI'
(Other definitions for elemi that I've seen before include "Extract" , "aromatic resin" , "Fragrant substance" , "It's fragrance" , "Resinous stuff" .)