#1 fill up v. make full, also in a metaphorical sense; "fill a container"; "fill the child with pride". wn #2 fill up v. become full; "The pool slowly filled with water"; "The theater filled up slowly". wn #3 fill up v. fill or stop up; "Can you close the cracks with caulking?". wn #4 fill up v. eat until one is sated; "He filled up on turkey". wn