照常
zhào cháng · HSK 7
as usual
照 (according to) + 常 (the usual/normal) = as usual
常 also shows up in 常常 (often) and 平常 (ordinary), so it always carries the sense of normal or habitual. 照 means according-to, so 照常 literally reads as according-to-normal: business as usual.
照 — 昭 (bright) phonetic + 灬 (fire radical)
照 is a semantic-phonetic compound. The bottom 灬 is a variant of 火 'fire', giving the meaning of light or illumination, while 昭 'bright' on top supplies the sound 'zhào' and reinforces the brightness sense. It originally meant to shine light on something, later extending to 'reflect', 'photograph', and 'according to'.
常 — 巾 (cloth) + 尚 (phonetic, 'esteem')
Originally written 裳, 常 was a phono-semantic compound: 巾 ('cloth') gave the meaning and 尚 supplied the sound, referring to a long lower garment or skirt. Over time the meaning shifted from 'everyday garment' to 'ordinary, regular, constant', while 裳 took over the original clothing sense.