Being a fan of or strongly supporting a particular idol, character, player, etc.; (the) person/character you support.
彼はAKBの推しに会うために握手会に並んだ。
He queued for the handshake event to meet his oshi from AKB.
友達とライブに行って、みんなで推しを応援した。
I went to the concert with friends, and we all cheered for our oshi.
推しがセンターになったと聞いて泣いてしまった。
I heard my oshi became the center and started crying.
One's favorite member/character/player (e.g., in an idol group, anime, or team); a slangy way to say 'favorite'.
私の推しはこのアニメのサブキャラです。
My oshi is a supporting character in this anime.
推しが卒業すると聞いてショックを受けた。
I was shocked to hear my oshi was graduating (leaving the group).
推し活でグッズを集めている。
I'm collecting merchandise as part of my oshi activities.