Denshi Jisho — Online Japanese dictionary

御睡 おねむ sleeping; being sleepy
Noun, Usually written using kana alone, Children''s langauge 
仮睡 かすい nap; siesta
Noun, Suru verb 
午睡 ごすい nap; siesta
Noun, Suru verb 
魔睡 ますい deep slumber (as if under a spell)
Noun 
麻睡 ますい anaesthesia; anesthesia
Irregular kanji usage, Noun, No-adjective 
昏睡 こんすい 1: lethargy; stupor;
2: coma; dead sleep
Common word, Noun, Suru verb, No-adjective 
一睡 いっすい (usu. in negative sentences) (not) a wink of sleep
Noun, Suru verb 
仮睡 うたたね nap; siesta
Irregular kana usage, Noun, Suru verb 
半睡 はんすい half asleep
Noun, Suru verb, No-adjective 
爆睡 ばくすい fast asleep; bombed; crashed
Na-adjective, Colloquialism 
微睡 まどろみ slumber; doze; nap
Noun, Usually written using kana alone 
熟睡 じゅくすい sound sleep
Common word, Noun, Suru verb 
半醒半睡 はんせいはんすい half awake and half asleep
Noun 

You can also

Look up kanji details for *睡.

Try a Yahoo Jisho search for *睡 .
Try a Goo Jisho search for *睡 .
Try a Google search for *睡 .