tumescent
Concise Oxford English Dictionary © 2008 Oxford University Press:
tumescent /tjʊˈmɛs(ə)nt/
▶adjective swollen or becoming swollen.
– derivatives
tumescence noun,
tumescently adverb.
tumescence noun,
tumescently adverb.
– origin C19: from L. tumescent-, tumescere ‘begin to swell’, from tumere ‘to swell’.
'tumescent' also found in these Oxford entries:

