Green’s Dictionary of Slang

1. (US, also gheed-up) drunk [? link to gee n.⁵ ].

1939		Flynn’s 18 Mar. 56/2: She fell from the doorway, either not knowing there were two steps down into the bathroom or else forgetting it on account of being so geed up [OED].
1950		Goldin et al. DAUL 77/2: Geed-up. Intoxicated.

2. (also G’d up) excited; in a positive mood.

1926		Sentee Men 118: Last night’s sign [...] still keeps me geed up some [HDAS].
1998		P. Doyle (con. late 1950s) Amaze Your Friends (2019) 18: Suitably geed up, I turned my attention to monetary matters.
1999		K. Sampson Powder 92: The group seemed quite geed-up by it too.
2005		R. Cea No Lights, No Sirens 36: I was so G’d up about this first chase, I leaped out of the car without placing it in park.

3. intoxicated by drugs [? link to gee n.⁶ ].

1937		B. Dai Opium Addiction in Chicago 199: Geed up. Filled with drugs.
1938		D. Maurer ‘Lang. of the Und. Narcotic Addict’ Pt 2 in Lang. Und. (1981).
1944		O. Ferguson ‘Vocab. for Lakes [etc.]’ in AS XIX:2 104: There is some allusion in sailors’ language to the use of drugs [...] gheed up [...] and goofed up are cognate and self-explanatory.
1949		Monteleone Criminal Sl. (rev. edn).
1952		Lannoy & Masterson ‘Teen-age Hophead Jargon’ in AS XXVII:1 25: GEED UP, phr. Under the influence of drugs [LAPD].
1959		J.E. Schmidt Narcotics Lingo and Lore.
1971		E.E. Landy Underground Dict. (1972).

4. (also g’d up) modified and thus increased in value.

1997–2000

College Sl. Research Project (Cal. State Poly. Uni., Pomona) 🌐 G’d up (verb phrase) Modified and made more valuable.