Lumbermen accepting fine: DA to direct piercing glare (4,7)

I believe the answer is:

look daggers

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

'direct piercing glare' is the definition.
'look daggers' can be an answer for 'glare' (I've seen this before). I am not sure about the 'direct piercing' bit.

'lumbermen accepting fine da' is the wordplay.
'lumbermen' becomes 'loggers' (I am not sure about this - if you are sure you should believe this answer much more).
'accepting' is an insertion indicator (inserted letters are accepted).
'fine' becomes 'ok' (synonyms).
'ok'+'da'='okda'
'loggers' going around 'okda' is 'LOOK DAGGERS'.

'to' is the link.

Can you help me to learn more?

(Other definitions for look daggers that I've seen before include "Glare" , "appear furious" .)

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.