No definitions found for 'heavy oil'
Perhaps one of these:
havilah,
hay bale,
hibol,
habile,
hpl,
havel,
hope hull,
hubly,
heavily,
hovel,
hebbel,
hoopla,
hobble,
hubble,
hable,
hubel,
hop pole,
haffle,
happily,
hoful,
hobbly,
hypohyal,
huffily,
hopple,
hoople,
hubbell,
hop fly,
hop flea,
hooppole,
haply,
hopewell,
hoi polloi