Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
aerūgo, ĭnis, f. [aes, as ferrugo from ferrum]. 
- I.  Rust of copper: aes Corinthium in aeruginem incidit, * Cic. Tusc. 4, 14; Plin. 15, 8, 8, § 34; 34, 17, 48, § 160.
 
- B.  Transf. 
 
- 1.  The verdigris prepared from the same: Aeruginis quoque magnus usus est, Plin. 34, 11, 26, § 110.
 
- 2.  In gen., rust of gold and silver: aerugo eorum (auri et argenti) in testimonium vobis erit, Vulg. Jac. 5, 3.
 
- 3.  Poet. (as pars pro toto, and sarcastic.), money, Juv. 13, 60.
 
- II.  Trop. 
 
- A.  Envy, jealousy, ill-will (which seek to consume the possessions of a neighbor, as rust corrodes metals): haec est Aerugo mera, Hor. S. 1, 4, 101: versus tincti viridi aerugine, Mart. 10, 33, 5; 2, 61, 5.
 
- B.  Avarice, which cleaves to the mind of man like rust: animos aerugo et cura peculi Cum semel imbuerit, Hor. A. P. 330.