Ancient skill in bridge-building (7)
I believe the answer is:
spartan
'ancient skill in bridge-building' is the definition.
I can't judge whether this definition defines the answer.
'ancient skill in bridge' is the wordplay.
'ancient skill' becomes 'art' (both can mean a talent. I am not sure about the 'ancient' bit.).
'in' indicates putting letters inside.
'bridge' becomes 'span' (synonyms).
'art' inserted within 'span' is 'SPARTAN'.
Can you help me to learn more?
(Other definitions for spartan that I've seen before include "Indifferent to luxury" , "austere old Greek" , "Frugal" , "Strictly disciplined" , "Rather austere" .)