Sibling avoiding second disturbance (6)
I believe the answer is:
bother
'disturbance' is the definition.
(I know that bother is a type of disturbance)
'sibling avoiding second' is the wordplay.
I cannot quite see how this works, but
'second' could be 'other' (I've seen this before) and 'other' is found within the answer.
A single letter 'b' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for bother that I've seen before include "Hassle - drat!" , "Take the trouble to do something" , "Worry, upset (someone)" , "Discommode, annoy" , "Fuss; oh no!" .)