Guide skirts small sign (6)
I believe the answer is:
gemini
'sign' is the definition.
(Gemini is a star sign)
'guide skirts small' is the wordplay.
'skirts' says to hollow out the word (remove centre letters) (retain the edges).
'small' becomes 'mini' (short for miniature).
'guide' with its centre taken out is 'ge'.
'ge'+'mini'='GEMINI'
(Other definitions for gemini that I've seen before include "May person" , "Sign of the Twins ( 6)" , "Zodiacal twins" , "Third zodiacal sign" , "Third sign of the Zodiac" .)