Geek abruptly, after blocking pieces, mates (8)
I believe the answer is:
partners
'mates' is the definition.
(I know this)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for partners that I've seen before include "Business or marital mates" , "Close associates in business or life" , "Companions or associates" , "They share in an activity, business or marriage" .)