Languid feeling that makes some of the children nuisances (5)
I believe the answer is:
ennui
'languid feeling' is the definition.
'ennui' can be an answer for 'feeling' (ennui is a kind of feeling). I am not sure about the 'languid' bit.
'some of the children nuisances' is the wordplay.
'some of' indicates the answer is hidden within the clue.
'ENNUI' is hidden in the letters of 'children nuisances'.
'that makes' is the link.
Can you help me to learn more?
(Other definitions for ennui that I've seen before include "Weariness with life" , "Lower interest rate" , "to make one list less when connected" , "Feeling of weariness or boredom" , "Boredom, dullness" .)