Dear, I play poker.
There is no such thing as a fiur card hand, a full house can only work with five cards or more, also straight flush and royal flush.
Now, a kicker is a card which determines the winner when two players have an equal hand. The kicker is only known as high when there are two equal hands, the one with the highest kicker gets to claim “whatever” high.
Eg., if two players have a pair of queens and a pair id sevens. One player has a jack, the other has an ace.
It is called as two pair with a jack kicker and two pair, ace high.