the inflation is a general rise in price level .there are various kinds of inflation like demand pull , cost push , core inflation, nfne inflation, trimmed inflation , creeping inflation, walking inflation, running inflation, hyper inflation etc.
while unemployment is a situation where a person is willing to work , is able to work , and some times gets the job but not according to his capabilities is called unemployment.there are various types of unemployment also , like structural unemployment, cyclical , disguised or voluntary unemployment etc.

BOTH ARE COLLECTIVELY CALLED AS TWIN EVILS
when we try to control inflation , the unemployment increases and when we try to control unemployment the inflation rises.
REASON:
when inflation is to control ,there is reduction in price level, this reduction causes the reduction in profit so production decreases and when production decreases few workers are required than before.