Modifiers matching duck:

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

Simple categories matching daffy:

• billionaire,
• person,
• recluse,
• duck,
• philanthropist,