Lady Groan flung what remained of the grain across the room and the stone-chat hopping from the bed-rail to her head, took off again from that rabous landing ground with a flutter, circled twice around the room steering during his second circuit through the stalactites of shining wax, and landed on the floor beside the grain.
(M. Peake; Titus Groan)
What does it mean?
As you can see here, it appears that Mervyn Peake invented the word.
Here is another theory: On the other hand, I believe that rabous (as in a bird taking off ‘from that rabous landing ground’) is probably an accident, a mis-transcription (that went unnoticed) of Peake’s manuscript by his typist. The MS of this passage no longer exists, but knowing the idiosyncracies of Peake’s handwriting, I feel sure that he wrote ‘rufous’, a reddish-brown colour, perfectly applicable to the Countess’s hair in which the bird had been perched.
Taken from Mervyn [Laurence] Peake: FAQ
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.