This is the 16362nd most frequent Polish word.
uśmiechał
"Uśmiechał" means "he was smiling" in English.
The word 'uśmiechał' is used here as a third person singular past tense verb, showing that Jan was smiling during the time he saw his dog.
Jan uśmiechał się, gdy zobaczył swojego psa.
Jan smiled when he saw his dog.
Here, the verb 'uśmiechała' (the feminine form of 'uśmiechał') is used in its past tense to indicate an ongoing action of smiling during a conversation.
Maria uśmiechała się przez całą rozmowę z koleżanką.
Maria was smiling throughout the entire conversation with her friend.
In this context, 'uśmiechał' illustrates a habitual action of smiling occurring repeatedly upon hearing good news.