Mammoth Uncensored Word List:
20 - 12 letter words starting with av

availability avariciously avascularity avengeresses averruncated averruncates averruncator aversenesses aversiveness aviatophobes aviatophobia aviatophobic aviculturist avitaminoses avitaminosis avitaminotic avowableness avuncularism avuncularity avunculizing