Having qualities like a gull; easily deceived or foolish; resembling or characteristic of someone who is gullible.
From 'gull' (a fool or the bird) plus the suffix '-ish' (meaning somewhat or resembling). The '-ish' suffix is one of the most productive in English for making informal adjectives.
The suffix '-ish' is fascinating—it adds vagueness intentionally. 'Gullish' means sort of foolish, not completely foolish, letting speakers express uncertainty or partial qualities.
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