(bound form) solid; firm; strong; secure; hard (not liquid or gaseous)

firmly; resolutely; stubbornly; persistently

(bound form) to strengthen; to make firm; to consolidate; to stabilize

admittedly; indeed; used in the first part of a sentence to acknowledge a fact before a transition, similar to 固然 gù​rán

originally; inherently; as a matter of course; undoubtedly; of course

surname Gu

(literary) to shut; to confine; to keep under restraint