GAttion
5 letter words beginning with g ending with L:grillgrowl
slingstungstingswingswung
Gauntness, Gauntlets
Gander, Gender, Grandmother, Glitter, Ghastlier, Greasier, Gardener, Godfather..gamblergangstergartergathergeargeographergeysergingergiverglaciergladiatorglamorglimmerglossiergolfergophergrandeurgreatergreetergrumpiergunpowdergusher
gourd
alongbagbegbringcaringclingclogchugdigdingdragearringfangflagflungfroggaggoinggonghanghunginningjigjogjugkinglaglegloglongluglungmugnagoblongpegpigpugragrangrigringrugsangslangslingslugsongspringstagstingstringstrongstungsungtagtogtwigusingwagwigwrong
Thing. Well, actually, both words end in the letter G. The above could be an answer, but here is a funnier one (well...sorta...) The Beginning is the ending of nothing and everything.
zigzag
vowing
gaffergamblergingerglaciergodfathergreetergrocergutter
agingalongbeingbringclangclingclungdoingdyingflingflunggoingprongslingstingstungswingswungthingthongtwangwrong
Gangstergangplankgoregalaxygumbogasgassygloriousglitzygrittygammagaudyglossygargantuangoon...are cool words.