I'm taken aback by Greek worker, one moving to find job (7)
I believe the answer is:
migrant
'one moving to find job' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'i'm taken aback by greek worker' is the wordplay.
'taken aback' says the letters should be written backwards.
'by' means one lot of letters go next to another.
'greek' becomes 'gr' (abbreviation for Greek).
'worker' becomes 'ant' (worker is a type of ant).
'im' in reverse letter order is 'mi'.
'mi'+'gr'+'ant'='MIGRANT'
Can you help me to learn more?
(Other definitions for migrant that I've seen before include "Person who has moved residence to another place" , "Animal moving seasonally" , "Moving across territories" , "Transient" , "Animal moving with the seasons" .)