1. Something which is not very important. English = trifle, triviality.
As a Verb or Adjective
1. To be very unimportant and not worth attention. English = (be) nothing, (be) trivial, (be) trifling, (be) insignificant.
2. To do nothing at all, usually because you are lazy or uninterested.
1. Used alone in response from your addressee to repeat something you have said to mean that you won't bother because what you said was not very important. English = 'It's nothing!', 'Forget it!', and so on.
2. Used alone to deny that you have done or said something. English = 'I haven't done a thing!', 'I've done nothing!', 'I didn't say anything at all!', and so on.
1. Used next to a verb or adjective to negate it, i.e., to mean that the action does not happen, or that something does not have that quality. English = not, don't, doesn't, didn't.