| 伺机 | sì jī | to wait for an opportunity; to watch for one's chance | |
| 窥伺 | kuī sì | to spy upon; to lie in wait for (an opportunity) | |
| 伺服 | sì fú | servo (small electric motor); computer server | |
| 伺服器 | sì fú qì | server (computer) (Tw) | |
| 观衅伺隙 | guān xìn sì xì | lit. to look for holes, and observe gaps (idiom); fig. to search out one's opponent's weak points; to look for the Achilles' heel |