The undertow was strong that day, making it unsafe to swim.

A current of water below the surface that moves away from the shore, often creating a risk for swimmers.
Swimmers should be cautious of the undertow at this beach.
The lifeguard warned about the undertow before the swim.
Children should not swim alone in areas with a strong undertow.
strong undertow
dangerous undertow
swimming in undertow
current
backwash
rip current
The swimmer was pulled under by the strong undertow.

A current of water below the surface that moves in a different direction from the surface flow.
The child struggled against the undertow at the beach.
Surfers need to be careful of the undertow when catching waves.
The lifeguard warned about the dangerous undertow in the ocean.
strong undertow
dangerous undertow
powerful undertow
current
flow
tide
There was an undertow of sadness in her voice.

A hidden or underlying influence or feeling that is not immediately obvious.
An undertow of fear gripped the crowd during the storm.
She felt an undertow of doubt about her decision.
His laughter had an undertow of bitterness.
emotional undertow
strong undertow
subtle undertow
subtext
implication
nuance