ADJ

eastern, western, etc.
Thousands were killed on the eastern front

VERB + FRONT

send sb to
Even young teenagers were sent to the front

PREP

at the ~
A new battalion arrived at the front
on the~
They had to fight on two fronts

ADJ

bold, brave

VERB + FRONT

put on
She put on a brave front, but I knew how miserable she was

PREP

~ for
Her aggressive behaviour is just a front for her shyness

PHRASES

present a united front
However much the directors disagree with each other, they always present a united front to the world