China's ready to overpower initially Cambodia and Thai peninsula (7)
I believe the answer is:
yucatan
'peninsula' is the definition.
(Yucatan Peninsula is an example)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for yucatan that I've seen before include "Mexican state" , "Region of Mexico" , "part of Mexico" , "Mexican peninsula where Mayas lived" , "N. Mexican peninsula" .)