Keep and kelp are four letter words starting with K and ending with P.
pour
scrip
plaza
zapp
pump
Some four letter words beginning with P and ending with S:PadsPalsPansPapsParsPassPatsPawsPaysPeasPecsPegsPensPepsPetsPewsPicsPiesPigsPinsPipsPitsPlusPodsPolsPomsPopsPotsProsPubsPudsPugsPunsPupsPuts
Keep and kelp are four letter words starting with K and ending with P.
weep
phiz. prez. putz.
pour
Battleship
up
dolllop. =\
tulip
bishop
limp