This is the 15629th most frequent Polish word.
sucho
"Sucho" means "dry" in English.
Here, "sucho" is used as an adverb to describe the general condition of the desert, emphasizing a lack of moisture.
Na pustyni jest sucho i gorąco.
In the desert, it is dry and hot.
In this case, "sucho" is used in conjunction with the verb "robił się" (became), reflecting the shift of the condition of the bread to a less moist state.
Mój chleb robił się sucho pamiętnego popołudnia.
My bread became dry on that memorable afternoon.
Here, "sucho" is used metaphorically as an adverb, to criticize the lack of expressiveness or emotionality in the manner of someone's speaking.