One train going around Spain is synonymous with those doing nothing (7)
I believe the answer is:
inertia
'doing nothing' is the definition.
(I've seen this before)
'one train going around spain is synonymous with those' is the wordplay.
I cannot really understand how this works, but
'one' could be 'i' (Roman numeral) and 'i' is found in the answer.
'spain' could be 'e' (abbreviation for Espana) and 'e' is located in the answer.
an anagram of 'train' is 'nrtia' which is located in the left over letters.
This accounts for all the letters.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for inertia that I've seen before include "Unresponsiveness" , "Way of selling" , "Sluggishness - sloth" , "Disinclination to respond" , "I earn it (anag.)" .)