/ ˈʌndətəʊ; NAmE ˈʌndərtoʊ/ noun [ usually sing. ]
1.
a current in the sea or ocean that moves in the opposite direction to the water near the surface :
The children were carried out to sea by the strong undertow.
2.
undertow (of sth) a feeling or quality that influences people in a particular situation even though they may not really be aware of it