This is the 11647th most frequent Russian word.
жестокими
"Жестокими" means "cruel" or "brutal" in English.
The word 'жестокими' here is an adjective in the instrumental plural form describing 'времена', showing that the times were characterized by cruelty.
Эти времена были жестокими для простых людей.
These times were cruel for ordinary people.
In this sentence, 'жестокими' is in the instrumental plural form modifying 'их', suggesting that the events caused them to become cruel.
События войны сделали их жестокими и бесчувственными.
The events of the war made them cruel and unfeeling.
Here, 'жестокими' describes the nature of the words ('словами'), emphasizing their cruelness in manner.