This is the 9790th most frequent Japanese word.
表立っ
"表立っ" means "to become public or overt."
Here, 表立った is used in the past tense to mean something has become public or apparent.
彼の秘密の計画は、ついに表立った。
His secret plan has finally come to light.
In this sentence, 表立って is used as an adverb meaning openly or publicly, describing the manner of action.
彼女は表立って自分の意見を述べるのが苦手だ。
She feels uncomfortable expressing her opinions publicly.
表立つ is used here in its dictionary form to suggest the manner of approach in dealing with the issue, implying transparency and openness.