IPA: /ˈsliːpɪnəs/
KK: /ˈslipɪnəs/
The state of feeling drowsy or wanting to sleep.
After a long day at work, I often feel a sense of sleepiness in the evening.
Sleepiness → It is formed from "sleep" (from Old English *slæpan*, meaning to rest or be in a state of sleep) and "-iness" (a suffix meaning the quality of). The word "sleepiness" refers to the quality of being in a state of sleep or the feeling of needing sleep.
Think of the state of 'sleep' and remember that 'sleepiness' means the quality of needing or being in sleep.