Q
Medium 1 Mark
English Synonyms & Antonyms
The very formal/literary synonym of 'big' among these is:
Explanation
'Prodigious' (also immense, colossal, gargantuan) is the very formal/literary register.
Reference: English Vocabulary: Synonyms & Antonyms (Complete Notes) , Page 4
Hint
Prodigious = impressively immense.