“ripe thoughts in my brain inhearse, Making their tomb the womb”
'Inhearse' means to enclose as in a hearse or coffin — to bury. The rival's verse has entombed the speaker's thoughts before they could be born into language. 'Ripe' means mature and ready to be expressed. The paradox in line 1194 — the brain becoming both tomb and womb — is the conceit: the same space that grew the ideas now seals them in.
“by spirits taught to write, Above a mortal pitch”
'Pitch' is a falconry term: the highest point of a hawk's flight before it stoops on prey. 'Above a mortal pitch' means verse that soars beyond what ordinary human ability can reach. 'Spirits' in the same line carries two meanings at once — inspiration (a routine Elizabethan synonym for creative energy) and actual supernatural beings — an ambiguity the sonnet deliberately develops in the next quatrain.
- TLN 1199historical topical
“affable familiar ghost Which nightly gulls him with intelligence”
In Elizabethan law and demonology, a 'familiar' was a demon or spirit bound to serve a witch or magician. 'Affable' means friendly, easy to approach. The phrase 'affable familiar ghost' is sardonic: the speaker reduces the rival's claimed divine inspiration to a cozy household demon. 'Gulls him' means deceives or tricks him; 'intelligence' means secret information. The rival is not inspired but duped.
historical The Fair Youth, the Dark Lady, and the Rival Poet