Dog not nervous of shooting (6)

I believe the answer is:

lassie

I'm a little stuck... Click here to teach me more about this clue!

'dog' is the definition.
(I've seen this before)

I don't understand how the rest of the clue works.

(Other definitions for lassie that I've seen before include "Scots girl - film dog" , "Cinema dog who went home" , "Girl from Scotland and dog from film" , "Screen mutt - Scottish girl" , "Young Scottish female" .)

I've seen this clue in the Evening Standard.

Want a hint initially instead of a full solution? Install my app