Modifiers matching vermin:

• dangerous,
• unwelcome,
• deadly,
• small,
• unwanted,
• voracious,
• poisonous,
• urban,
• vicious,
• undesirable,

Simple categories matching vicious:

• predator,
• critter,
• creature,
• animal,
• vermin,
• monster,
• mammal,
• beast,