tailor, judge, decision, cut out (pattern)
裁 centers on cutting with authority: physically cutting cloth to tailor a garment, and metaphorically cutting through a dispute to judge or decide. The pattern sense is the result of that cutting.
裁 combines 衣 (clothing) with a phonetic component that also suggests cutting or dividing. The character originally referred to cutting cloth to make clothes, and later extended to judging or deciding.
Inside the outer structure, see 衣 (clothing). Imagine a tailor using scissors to cut a pattern out of fabric: the cutting action is both physical (tailoring) and decisive (judging).
For サイ, picture a tailor cutting a suit with a sharp sigh of concentration: sigh -> サイ, as the scissors slice through the cloth.
trial; judgement; judgment
court; courthouse
judge
president (of an organization); director general; governor (of a central bank); party leader (esp. LDP)
dictatorship; despotism; autocracy
sanctions; punishment
district court
Supreme Court
to judge; to try; to sit in judgement (on); to decide (on)
discretion; judgement; judgment
(outward) appearance
High Court
sewing; needlework
arbitration; intercession; mediation
decision; ruling; award; arbitration
sanction; approval; decision
decision; ruling; judgement; judgment
family court
(Western) dressmaking
summary court; court of summary offences
to cut (cloth)
judicial trial