na-adjective
re-entrant
Computing term describing a function or subroutine that can be safely called again before a previous invocation has completed, typically because it does not rely on shared mutable state.
この関数は再入可能なので、割り込みハンドラから安全に呼び出せます。
This function is re-entrant, so it can be safely called from an interrupt handler.
再帰的 (recursive) describes a function that calls itself, while 再入可能 (re-entrant) describes a function that can be safely interrupted and called again before it finishes.
Compound of 再入 (re-entry) + 可能 (possible), likely a calque of English 're-entrant'.