What is the base form of this word?
In dictionaries, 形 is sometimes used as an abbreviation for 形容詞 (i-adjective).
formation; shaping; creation · repair (plastic surgery); replacement; -plasty
form; shape; figure · morph
shape; form
orthopedics; plastic surgery; cosmetic surgery · shaping; smoothing; fairing
transformation; deformation; modification; variation; metamorphosis
molding; shaping; forming; modeling
terrain; topography; geographical features
round shape; circle; circular form
fixed form; regular shape; set pattern · standard-size mail
beautiful face; beautiful looks · beauty; belle; handsome man
triangle
figure; shape; graphic
forming; shaping; fashioning · molding; casting; compacting · adult form
trace; sign; evidence
variant; variant form · heteromorphism; heteromorphy
wavy form; ripply shape · waveform
deformity; malformation · strange shape; unusual shape
solid; solid body
description; expression in words; figurative expression · grammatical modification; qualification · form; figure; appearance
formless; intangible; abstract
battle formation; military formation
linear
-gon
situation; state of affairs; prospects
quadrilateral; quadrangle; tetragon
same shape; isomorphism; same type; same pattern
tangible; material; concrete
lifeless body; corpse · framework; skeleton; remains · mere shell; empty form; dead letter
external form; outer shape; externals
The kanji 形 means 'shape' or 'form'. As a suffix, it derives from this meaning, used in linguistic terminology. The abbreviation sense comes from the first character of 形容詞.