The word “Apikoros” is completely misused by most people. Basically, they imply that if you don’t believe in the Yeshivish hashkofos you are an apikoros. However, those who take this position fail to realize that many many great Gedolim did not have the same Hashkafos as R’ Aharon Kotler Zt”l.
Although not directly related, it may be useful to quote R’ Shimon Schwab Zt”l :
” While we do not insist that only “Torah Giants” come forth from our great yeshivos, we are certainly not anxious to put up with any “Torah dwarfs” either. By this we mean the overly inflated semi-scholar, whose knowledge of Neviim and Kesuvim is nil and whose acquaintance with Shisha Sidrei Mishna is pitiful. These individuals are only vaguely familiar with halachah and aggadah, and their encounter with hashkafah literature is confined to two or three books. Sadly enough, some of these people become self-styled experts on daas Torah today” – Selected Essays, page 144