Host finally cut off very vacuous swimmer (7)
I believe the answer is:
anchovy
'swimmer' is the definition.
(anchovy is a kind of fish)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for anchovy that I've seen before include "Salty little fish" , "Small, salty-tasting fish" , "Small fish of herring family, nice on toast" , "Brit often found pickled" , "Small edible fish" .)