To live at the East End is a chancy thing to do (3)
I believe the answer is:
bet
'a chancy thing to do' is the definition.
I can't judge whether this definition defines the answer.
'to live at the east end' is the wordplay.
'to live' becomes 'be' (synonyms).
'the east end' says to take the final letters (the letter on the right or east end of the word).
The last letter of 'at' is 't'.
'be'+'t'='BET'
'is' acts as a link.
Can you help me to learn more?
(Other definitions for bet that I've seen before include "22 across will accept one" , "Speculation" , "Money risked on a gamble" , "'Stake, wager (3)'" , "Wager, gamble" .)