Figure Igor had been led astray by the sign (5)
I believe the answer is:
virgo
'the sign' is the definition.
(Virgo is an example)
'figure igor had been led astray' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'igor' is 'irgo' which is within the answer.
A single letter 'v' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
'by' acts as a link.
Can you help me to learn more?
(Other definitions for virgo that I've seen before include "Sixth sign of zodiac" , "Large constellation between Leo and Libra" , "Star sign" , "Large constellation -- sign of the zodiac" , "Zodiacal sign" .)