What is glooi in English?
Warning! The plant and tuber may be poisonous and must be cooked by experts. See comments.

Some Thai friends had eaten this tuber when they were young and helped me surf the Internet for it.

It is pronounced glooi (กลอย).

Scientifically it would be
Dioscorea hispida Dennst
http://www.thaicrudedrug.com/main.php?action=viewpage&amp;pid=14

My dictionary translates it as wild yam, but that is probably a wide definition. It is definitely different from other yam that resembles sweet potato and  is sometimes purple. (Yam in Thai language is "man".)