Find NLTK Wordnet Synsets for combined items in a list

Question

I am new to NLTK. I want to use nltk to extract hyponyms for a given list of words, specifically, for some combined words

my code:

import nltk 
from nltk.corpus import wordnet as wn


list = ["real_time", 'Big_data', "Healthcare",
        'Fuzzy_logic', 'Computer_vision']



def get_synset(a_list):
    synset_list = []
    for word in a_list:
        a = wn.synsets(word)[:1] #The index is to ensure each word gets assigned 1st synset only
        synset_list.append(a)
    return synset_list


lst_synsets = get_synset(list)
lst_synsets

Here is the output:

[[Synset('real_time.n.01')],
 [],
 [Synset('healthcare.n.01')],
 [Synset('fuzzy_logic.n.01')],
 []]

How could I find NLTK Wordnet Synsets for combined items? if no, any suggestion to use one of these methods for combined terms?