资料来源 : pyDict

伸缩自如的,缩回的,收缩的

资料来源 : Webster's Revised Unabridged Dictionary (1913)

Retractile \Re*tract"ile\, a. [Cf. F. -r['e]tractile.]
   (Physiol.)
   Capable of retraction; capable of being drawn back or up; as,
   the claws of a cat are retractile.

资料来源 : WordNet®

retractile
     adj : capable of retraction; capable of being drawn back; "cats
           have retractile claws" [ant: {nonretractile}]