Borusyak, 2021 has a sentence
First, we note that failing to rule out anticipation effects in “fully-dynamic” specifications (with all leads and lags of treatment included) leads to an underidentification problem, where the dynamic path of anticipation and treatment effects over time is not point-identified
I am wondering what do "underidentification" and "point-identified" mean in this case? I ask these words here because these words are not in the vocabulary (I checked with Cambridge dictionary) and I believe it belongs to econometrics words.