TUNNEL is validvalid

to dig an underground passageway [v TUNNELED, TUNNELING, TUNNELLED, TUNNELLING, TUNNELS] : TUNNELER [n]

30,109 of 196,601 in NWL2023·also valid in CSW24

an underground passageway [n -S] / to dig a tunnel [v TUNNELED or TUNNELLED, TUNNELING or TUNNELLING, TUNNELS]