Meaning : In essence. At bottom or by one's (or its) very nature.
Example :
He is basically dishonest.
The argument was essentially a technical one.
For all his bluster he is in essence a shy person.
Synonyms : basically, essentially
Fundamentally ka meaning, vilom shabd, paryayvachi aur samanarthi shabd in Hindi. Fundamentally ka matlab kya hota hai?