Learned helplessness is the condition when we’re so used to being able to do nothing that we, in effect, give up trying to do anything – even though the circumstances might have changed so that we could do something if we tried.
It can be learned by animals when given electric shock and by babies who, for example, get no feedback from their mother: They learn that nothing they do gets any response. (Presumably human babies can also learn it from receiving unavoidable electric shocks, but to my knowledge this particular scientific experiment has never been published!)
As you can imagine, it can have massive implications for us as adults – if we believe nothing much we do can influence how things will turn out we’re fare less likely to try and do anything to improve our situation. We’re therefore much, much less able to be able to cope when things go wrong.