only a properly created cold storage or a trusted hardware wallet.
you can search for some hardware wallets if you are not tech savvy or don't want to bother learning how tos and if you are willing to pay. things such as Trezor or Ledger nano would work.
or you can learn more about cold storage and do it yourself easily. like creating a paper wallet with tools such as
https://github.com/pointbiz/bitaddress.org or make a Trezor like cold storage on your USB disk yourself
https://en.bitcoin.it/wiki/Cold_storageI would recommend you to use some hardware wallets.
You cab pay and get like Trezor or Ledger Nani.
To be added cold storage is an offline wallet which cannot be accessed you can even safer your bitcoin here also it cannot be hacked.
How ever you could even out an USB stick and hold your BTC there in offline mode, hacking is not possible in this way.