Modifiers matching duck:

• unusual,
• jealous,
• tenacious,
• rare,
• small,
• marine,
• smaller,
• optimistic,
• daffy,
• short-tempered,
• here,
• insecure,
• slobbery,
• determined,
• lisping,
• breeding,
• native,
• boastful,
• domestic,
• paranoid,
• zany,
• bullying,
• larger,
• brash,
• large,
• aggressive,
• wild,
• common,
• pushy,
• indigenous,

Simple categories matching here:

• process,
• activity,
• duck,