Modifiers matching duck:

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

Simple categories matching here:

• process,
• duck,
• activity,