キチ, キツ, よし, え, き, きっ, きる, こし, と, よ
good luck, joy, congratulations
JLPT1 G7 S6 F711
A depiction of a (filled) container (compare 器) → *good luck*; *favorable* (← abundance ← abundant contents). In derivative characters such as 佶 桔 and 詰, 吉 exerts the conceptual influence "reduce/eliminate space." For the connection between abundance and good fortune, compare 祺.
[Full Kanji Etymology List]