This means that there is not tax due on the gain unless or until the money is withdrawn. (termlife360.com)
For example, the growth of this cash is allowed to increase on a tax - deferred basis, meaning that there will be no income tax due on the gain until the time it is withdrawn. (truelifequote.com)
There's now no Capital Gains Tax due on gains arising before that date. (money.stackexchange.com)