What does the cryptic crossword clue "Fat cat sees gerbil with ague shivering (3-7)" mean?

The definition is "Fat cat sees". The wordplay uses an anagram. anagram of GERBIL AGUE = BIGLEAGUER The answer is BIGLEAGUER.

Fat cat sees gerbil with ague shivering (3-7)

Guardian Cryptic #29365 | 13 Down | 2024-04-24 flower