Its 100% possible to hack your bitcoin wallet. But you if awere of it and take some precaution, the change of hacking almost zero.There are many ways hacker use to hack. one of them is phishing.You have to concious about it.We you open any wallet, check theck the url.don't be greedy to see any offer like "0.5 btc within 15 minutes ".If your wallet have 2 way authentication, don't be lazy to implement it.
Everything is possible but not everything works. You cant hack someones bitcoin wallet easily and get away with it like its nothing. But i suggest to put your coins in some other wallets as well so that if 1 gets hacked you still have coins left.