Extremely uncertain when passing on something permanent? (7)
I believe the answer is:
undying
'permanent?' is the definition.
(thesaurus)
'extremely uncertain when passing on' is the wordplay.
'extremely' says to hollow out the word (remove centre letters) (letters on the extremes of the word are used).
'when passing' becomes 'dying' (I can't justify this - if you can you should give a lot more credence to this answer).
'on' says to put letters next to each other.
'uncertain' with its centre taken out is 'un'.
'un'+'dying'='UNDYING'
'something' is the link.
I am not very happy about this link. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for undying that I've seen before include "Lasting forever, not subject to mortality" , "Inextinguishable" , "Everlasting" , "Immortal, eternal" , "Constant" .)