The sort of clash in which the boss is appearing (4-2)
I believe the answer is:
head-on
'the sort of clash in' is the definition.
I can't tell whether this defines the answer.
'the boss is appearing' is the wordplay.
'the boss' becomes 'head' (I've seen this before).
'is appearing' becomes 'on' (e.g. on stage or on television).
'head'+'on'='HEAD-ON'
'which' is the link.
Can you help me to learn more?
(Other definitions for head-on that I've seen before include "Of car crash, full frontal" , "Frontal, collision say" , "This collision is full frontal" , "In direct opposition" , "Collision happening in full-frontal way" .)