bull's eye, mark, target, object, adjective ending
的 centers on a precise point of focus: a literal target like a bull's eye, a figurative mark or object, and the grammatical ending that turns a noun into an adjectival target.
-ical; -ive; -al; -ic; -y
purpose; goal; aim; objective; intention; motive
overwhelming
comparatively; relatively
intellectual
legal
sexual (i.e. relating to biological sex)
thorough; exhaustive; complete
target
automatic
public; official
private; personal
definite; final; decisive; conclusive
dramatic; exciting; touching
direct
accurate; precise; exact; appropriate; apt; right
human; personal
ground-breaking; revolutionary; unprecedented; epoch-making
hitting the target; striking home
great; grand; extensive; large-scale
frank; direct; plain; straightforward; point-blank; concise
humane
quantitative; concerning the quantity
material; physical
的 combines 白 (white) and 勺, which likely contributes the sound. The original meaning is a bright white target or mark, from which the abstract and grammatical uses developed.
The left side 白 (white) suggests a bright white spot, and the right side 勺 looks like a ladle or a mark. Imagine a white target with a ladle-shaped bull's eye: 的 is the mark you aim for.
For テキ, picture a techie aiming a laser pointer at a target: techie -> テキ, and the red dot hits the bull's eye.