Nonchalant during escape, one ought to be strung up (5,5)
I believe the answer is:
fairy light
'one ought to be strung up' is the definition.
I don't know anything about this answer so I can't tell whether this works.
'nonchalant during escape' is the wordplay.
'nonchalant' becomes 'airy' (airy can mean casual or unconcerned).
'during' means one lot of letters goes inside another.
'escape' becomes 'flight' (synonyms).
'airy' put within 'flight' is 'FAIRY LIGHT'.
Can you help me to learn more?
(Other definitions for fairy light that I've seen before include "one lit on tree perhaps" , "Decorative twinkler" .)