Sticky, slimy, or gooey; resembling or full of guck.
From guck + -i (informal adjectival suffix, sometimes -y). A casual, colloquial formation following the pattern of gooey from goo.
Gucki (or gucky) is the kind of playful adjective that kids invent naturally—when you have a noun that sounds squishy, adding -y makes it sound even squishier, which is exactly what the word needs.
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