at worst; if worst comes to worst; (usu. in the negative) serious; ala
大 · 3 strokes
Depicts an adult man facing forward and standing erect. The meaning later shifted to "big".
不 · 4 strokes
Pictograph of sepals of a flower. The modern meaning "no" is a phonetic loan.
了 · 2 strokes
Pictograph of a young child, similar to 子, but without arms. Compare to 孑 (child only with right arm) and 孓 (child only with left arm). The current meaning is a phonetic loan.