deponent
Concise Oxford English Dictionary © 2008 Oxford University Press:
deponent /dɪˈpəʊnənt/
▶adjective Grammar denoting verbs which are passive or middle in form but active in meaning. ▶noun Law a person who makes a deposition or affidavit under oath.
– origin ME: from L. deponent-, deponere ‘lay aside, put down’.
'deponent' also found in these Oxford entries:

