This is the 570th most frequent Croatian word.
suradnji
"Suradnji" means "cooperation" or "collaboration" in English.
Here, 'suradnji' is in locative case, indicating the state or setting of collaboration.
Uvijek sam zahvalan na suradnji s kolegama.
I am always grateful for the collaboration with colleagues.
In this context, 'suradnji' is used with 'u' to denote involvement in a cooperative effort.
Pohvaljujemo te za tvoj trud u suradnji s drugim odjelima.
We commend you for your effort in collaboration with other departments.
The word 'suradnji' here signifies the means by which something was achieved, associated with mutual effort.