Synonyms for Fixation (same or very similar meaning)
WordNet sense 1 (an abnormal state in which development has stopped prematurely):
regression, arrested development, infantile fixation
WordNet sense 2 (an unhealthy and compulsive preoccupation with something or someone):
obsession
WordNet sense 3 ((histology) the preservation and hardening of a tissue sample to retain as nearly as possible the same relations they had in the living body):
fixing
From the ODE community, based on WordNet
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