Sentence:  Psychoanalytic theory...seemed to promise to introduce a certain becoming amplitude into discussions of what different people are like — only to turn, in its streamlined trajectory across so many institutional boundaries, into the <WSD>sveltest</WSD> of metatheoretical disciplines, sleeked down to such elegant operational entities as "the" mother, "the" father, "the" preoedipal, "the" oedipal, "the" other or Other. 
Meaning of the word marked with <WSD> tags:  Attractively thin; gracefully slender. (from 1810s)