English Vocabulary Flash Cards @ englishpdf.com and englishteststore.com File 011 accustom (v) To make familiar by use acerbity (n) Sourness, with bitterness and astringency acetate (n) A salt of acetic acid acetic (adj) Of, pertaining to, or of the nature of vinegar ache (v) To be in pain or distress Achillean (adj) Invulnerable achromatic (adj) Colorless, acid (n) A sour substance