To the hilt(phrase)
Unable to be attacked, questioned, or defeated.
Hindi meaning:पूर्णतया
Synonyms: Completely, Wholly, Unconditionally, Fully, To the limit
Antonyms: Partially, Barely, Inadequately
Example: We're ready to defend our client to the hilt in court.
Trick to remember: Hill pe fort To the hilt ke liye bnaya jata hai. 
