This is the 4092nd most frequent Polish word.
atakujących
"Atakujących" means "attacking" or "assailants" (genitive or accusative plural form).
In this sentence, 'atakujących' is used as an adjective in plural, describing the 'enemies' (l.p. 'nieprzyjaciele') as the agent of the verb implying an ongoing action of attack.
Żołnierze bronili się przed atakującymi nieprzyjaciółmi.
The soldiers defended themselves against the attacking enemies.
Here, 'atakujących' functions as an adjective, modifying 'hyenas,' who are described as performing the action of attacking.
Lwy zaskoczyły atakujących hieny na otwartej równinie.
The lions surprised the attacking hyenas on the open plain.
In this context, 'atakujących' operates as a noun (also used substantively as an adjective) referring directly to those who attack, emphasizing the subject.