Meaning of some terms!!!

[zoobinshid]

Hello everybody,
Would you please tell me the meanig of these sentences?

1)A thick skinned man.
2)Pick a fight.
3)flack jacket.
4)A soft spoken man.
5)It becomes second nature.
6)This world and the here after.

Thanks in advance,

[Tdol]

1 doesn't take offence easily
2 start a fight without any real provocation
3 jacket top protect from shrapnel, etc (flak- http://www.answers.com/flak&r=67)
4- quiet voice
5 you can do it without thiking
6 this world and whatever comes after death