In the WordNet synsets, there are a bunch of concepts such as hyponyms, hypernys, holonyms and meronyms in the NLTK library.
Can someone explain these terms and maybe provide a few examples for this?
Wordnet is well-documented (there is even a book). This is perhaps the docs page that most directly answers your questions: https://wordnet.princeton.edu/documentation/wngloss7wn
Also, the terms are from linguistics, not invented by the WordNet team. So dictionaries will be useful. Or you can even get meta about it, and look them up in Wordnet :-)