adjective/ky.ky/
corny, cheesy, tacky, twee; silly, ditzy, dopey; gullible, naive
“Elle a prétendu au jardinier que le massif de silènes et de myosotis faisait cucu… J'en ris encore.” — She told the gardener that the bed of campions and forget-me-nots looked tacky… That still makes me laugh.
Reduplication of cul.