Green’s Dictionary of Slang

a term for the old (and middle-aged).

1982		N. Keesing Lily on the Dustbin 50: ‘Geris’ are geriatric patients but also may be rigid and unpopular senior nurses.
1986		C. Bowles G’DAY 19: If you’re old and feeble you’re a gerrie, and you probably wear a singie under your nightie, and a: cardie as well.
1993		M. Dibdin Dying of the Light 79: They don’t tear their hair or foam at the mouth, my little gerries.
2003		McGill Reed Dict. of N.Z. Sl.