IPA: /ˈɪkiər/
KK: /ˈɪkiər/
More unpleasant or disgusting than something else.
The old food in the fridge was even ickier than I expected.
Ickier is derived from the word 'icky' (a colloquial term meaning unpleasant or disgusting) with the comparative suffix '-er' (indicating a higher degree). The word 'ickier' means more unpleasant or more disgusting than something else.
Think of 'icky' as something unpleasant, and remember that 'ickier' means even more unpleasant.