Like a needle to be in a precarious state (4,2,1,6)
I believe the answer is:
hang by a thread
'be in a precarious state' is the definition.
(I've seen this before)
'like a needle' is the wordplay.
I cannot quite see how this works, but
'like' could be 'y' (similar in meaning) and 'y' is present in the answer.
'a' could be 'an' and 'an' is found within the answer.
This explanation may well be incorrect...
'to' is the link.
Can you help me to learn more?
(Other definitions for hang by a thread that I've seen before include "Depend on precarious conditions" , "Survive precariously" , "precariously placed" , "Be in a precarious state" .)