1
to brace one's legs;to stand firm;to plant one's feet (firmly on the ground)
群衆に押されないよう力を入れて踏ん張った。
I braced myself against the crowd.
2
to hold out;to persist;to make an effort;to exert oneself
土壇場で踏ん張ってその契約を勝ち取らない限り、我々は破産も同然だ。
If we don't make a last ditch stand at winning that contract, we may very well go under.
Other forms
踏んばる 【ふんばる】 (search-only kanji form)