It's very hard to be the first man to take on a worker (7)
I believe the answer is:
adamant
'it's very hard' is the definition.
I can't judge whether this definition defines the answer.
'be the first man to take on a worker' is the wordplay.
'be the first man' becomes 'adam' (I've seen this before).
'to take on' says to put letters next to each other.
'a worker' becomes 'ant' (worker is a type of ant).
'adam'+'ant'='ADAMANT'
'to' is the link.
Can you help me to learn more?
(Other definitions for adamant that I've seen before include "Unpersuadable" , "Refusing to change opinion" , "Impervious to pleas or persuasion" , "intractable" , "Refusing to budge" .)