This is the 8659th most frequent Korean word.
가장해
"가장해" means "to pretend" or "to fake."
Here, '가장했지만' means pretended, showing the act of pretending or feigning something, usually an attribute or state.
그는 부자처럼 가장했지만, 사실은 가난한 사람이었다.
He pretended to be wealthy, but in reality, he was a poor person.
In this sentence, '가장 행복한 척했는데' uses the word to mean pretending outwardly or acting as if one feels a certain way.
그녀는 모두 앞에서 가장 행복한 척했는데, 속으로는 슬펐었다.
She acted like she was the happiest in front of everyone, but she felt sad inside.
Here, '가장해 가며' reflects the usage where the person pretends to alter their identity or attributes during interaction.