The standard grips this chord is usually shown with.
GmMaj7 is G, Bb, D and F# — Gm with the major seventh added on top.
It sounds tense and wrong-footed. A minor triad carrying a major seventh: the semitone under the root over a minor chord is the first bar of a line cliché.
Minor tonic — the tonic of the melodic minor.

| G | Bb | D | F# |
|---|---|---|---|
| 1 | ♭3 | 5 | 7 |
Also written GmM7, Gm(maj7), G-Δ7 or GminMaj7. The same chord either way; which spelling you meet depends on who wrote the chart.
GmMaj7 in root position puts G in the bass, which is the chord as it is spelled: the note it is named after underneath everything else.
6 of GmMaj7’s 7 common shapes do this:310032xx5332354333xx5776x-10-8-7-7-xx-10-12-11-11-10
Play GmMaj7 as a shell — root, third and seventh — and the spare string takes the 9 (A), the 11 (C) or the 13 (E).
All 7 common shapes as fret numbers, lowest string first. Hover or tap one to see it drawn.
How you get to it. The turn that lands on GmMaj7 is Am7♭5 to D7♭9: the ii and the V of G minor, which is where a minor tonic is usually arrived at rather than simply begun on.
Every note of GmMaj7 is in G harmonic minor and G melodic minor.
Change one note of GmMaj7 and you have Gm (drop the major seventh), Gmaj7 (the minor third becomes the major third), Gm6 (the major seventh becomes the sixth), Gm7 (the major seventh becomes the flat seventh), GmMaj7b5 (the fifth becomes the flat fifth) or GmMaj9 (add the ninth).
GmMaj7 is a minor chord — root, minor third, fifth. Minor chords on every root.
The common shapes and the derived voicings come from different places, and both are explained in how this site is built.
Shows each chord the way this style would voice it, and marks which of its alternatives belong to the idiom.