Adumbrate is a verb which has four meanings (greedy). They are:
To represent in outline. As in ‘I adumbrated the idea of how to make the perfect gin and tonic.’
To indicate faintly. As in ‘the kitchen was only adumbrated by the light from the fridge as I poured my gin and tonic’.
To overshadow. As in ‘Emma’s plans to vacuum her flat were adumbrated by her need for a gin and tonic’.
To foreshadow a future event. As in… well, I can’t think of a gin and tonic-related example of this, so I’ll just give you the one on the OED page: ‘tenors solemnly adumbrate the fate of the convicted sinner’. Ooer. You might need a gin after that.
Now, I know all my readers are super clever, so you’ve probably already clocked some of the etymology here. The ‘umbrate’ bit comes from ‘umbra’, which is Latin for shadow. Other words we get from ‘umbra’ include: ‘umbrella’ (obvs – because it gives shade); umbrageous (future word of the week) which means (spoiler alert!) ‘affording shade’; and ‘umbrage’ as in ‘Professor’ and ‘to take offence’. In the past (vague, sorry) ‘umbrage’ was also a synonym for ‘shadow’. For an example of this see a poem (which doesn’t seem to have a name) by one William Drummond of Hawthornden:
‘About her flow’d a gowne as pure as light; Deare amber lockes gave umbrage to her face.’