A nickname that is commonly used for Grandparents and Great Grandparents. The name generally is used for attractive great grandparents, who are with younger women or men.
1. Me and Grump went to brunch this morning.

2. Grump is sexy.
by Char777 February 2, 2019
“A mythical Creature so elusive that to actually see one would bring untold good fortune” referenced in the movie One Week
I’m going to ride my motorcycle across Canada in search of Grumps
by I_M_CDN November 11, 2010
To add an entry on Grumper.
I posted a grump today at Grumper.org, check it out!
by Asyra June 11, 2009
To take from, either Violently, Sexually, or Passively
1. Im gonna grump that bitches V-card tonight when shes wasted.
2. Im gonna go grump some fresh chipolte
3. Im going to grump your life on Call of Duty 4.
by fresh grundle November 28, 2008
The act of kissing, possibly groping someone but there is no evidence to prove it.
I grumped her I did
by grb2011 October 29, 2011