IPA: /ˈtriːkli/
KK: /ˈtrikli/
Something that is excessively sweet or sentimental, often to the point of being unpleasant.
The movie was so treacly that I couldn't take it seriously.
Comparative: more treacly
Superlative: most treacly
Treacly is derived from the word 'treacle' (from Old French *tracle*, meaning a medicinal syrup) combined with the suffix '-y' (meaning characterized by). The word 'treacly' describes something that is syrupy or overly sweet, often in a figurative sense.
Think of 'treacle' as a thick, sweet syrup, and remember that 'treacly' means something that is characterized by being overly sweet or syrupy.