光说不练

guāng shuō bù liàn

all talk and no action (idiom)

to preach what one does not practice; same as 光說不做|光说不做[guang1 shuo1 bu4 zuo4]

光

guāng

light; ray (CL:道[dao4])

说

shuō

to speak; to talk; to say

不

bù

no; not so

练

liàn

to practice