(cì) to wait on
(sì) to watch; to wait; to examine; to spy
(cìhòu) to serve; to act as a valet
(sìfú) servo (small electric motor); computer server
(sìfúqì) server (computer)
(sìjī) to wait for an opportunity; to watch for one's chance
(sìxì) to wait for the opportunity