半路杀出个程咬金

bàn lù shā chū gè chéng yǎo jīn

lit. Cheng Yaojin ambushes the enemy (saying)

fig. sb shows up unexpectedly and disrupts the plan; sb whose presence is regarded as irksome

半

bàn

half

路

lù

road (CL:條|条[tiao2])

杀

shā

to kill; to slay; to murder; to attack

出

chū

variant of 出[chu1] (classifier for plays or chapters of classical novels)

个

gè

variant of 個|个[ge4]

程

chéng

rule

咬

yǎo

variant of 咬[yao3]

金

jīn

gold