Is led to ruin inside and passes time fruitlessly (5)
I believe the answer is:
idles
'passes time fruitlessly' is the definition.
I can't judge whether this defines the answer.
'is led to ruin inside' is the wordplay.
'to ruin' indicates an anagram.
'inside' means one lot of letters goes inside another.
'led' is an anagram of 'dle'.
'is' enclosing 'dle' is 'IDLES'.
'and' acts as a link.
Can you help me to learn more?
(Other definitions for idles that I've seen before include "Avoids working" , "Wastes time" , "Lazes about, just ticks over" , "Of engine, just ticks over in neutral" , "Lazes around" .)