Enough,
4 letter words ending in gh are high and sigh.
Some words ending with the letters "gh" pronounced as "f" are: rough, tough, enough, cough, laugh.
cough, enough, rough, tough, ...
A five letter word that end's with gh, is burgh.
tough
dough
Laugh, cough, rough, tough
ghost
graph, telegraph, phonograph, glyph, tough, rough, enough, cough, slough, trough
ghag
tough, cough, bough, rough