to complete; to accomplish
完 · 7 strokes
Phonosemantic compound. 宀 represents the meaning and 元 represents the sound. The 宀 component is used because putting on a roof completes the process of constructing a building.
成 · 6 strokes
Depicts defending city walls (丁) with an axe (戌). 丁 also represents the sound. Based on the original meaning "city", now written as 城. The current meaning is a phonetic loan.