Give a greeting to surprise the workers (5,5)
I believe the answer is:
shake hands
'give a greeting to' is the definition.
I can't judge whether this defines the answer.
'surprise the workers' is the wordplay.
'surprise' becomes 'shake' (I am not sure about this - if you are sure you should believe this answer much more).
'the workers' becomes 'hands' (hand is a kind of worker).
'shake'+'hands'='SHAKE HANDS'
Can you help me to learn more?
(Other definitions for shake hands that I've seen before include "Finalise agreement" , "Greet" .)