Sleepy
い adjective
This is a single kanji with an い on the end, meaning you know it's probably an adjective. What's the adjective form of sleep? It's sleepy.
ねむい
You're so sleepy you can't even remember your own name (ねむ).
昨日はよく眠れなかったので、今すごく眠いです。
I couldn't sleep well last night, so I am very sleepy now.
朝コーヒーを飲まないとすぐに眠くなってしまうんです。
If I don't drink coffee in the morning, I become sleepy quickly.
やばい、眠すぎる。
Oh no, I'm too sleepy.
渋滞に巻き込まれた時、目も開けていられないくらい眠い状態でもありました。
When I was caught in the traffic jam I was also so sleepy that I could barely keep my eyes open.