Sonnet 72

Devouring Time

Notes

TLN 995archaic vocab
“lest the world should task you to recite”
'Task' here means to call to account, to challenge someone to perform a duty. The poet fears the world will demand that the beloved explain what merit the poet possessed to deserve such love. OED records 'task' as a verb meaning 'to impose a task or burden on' and 'to call to account' from the sixteenth century.
TLN 999rhetorical device
“devise some virtuous lie, To do more for me than mine own desert”
A 'virtuous lie' is a deliberate falsehood told for a kind purpose — praising a man who deserves no praise. The phrase is an oxymoron, pairing a moral virtue with a moral wrong, and it captures the whole sonnet's predicament: genuine love for a worthless person can only express itself dishonestly. 'Desert' means what one deserves by right, here the poet's honest (and poor) due.
historical The sonnet form
TLN 1001archaic vocab
“hang more praise upon deceased I Than niggard truth would willingly impart”
'Niggard' means miserly, stingy, begrudging. 'Niggard truth' is honest assessment figured as a miser who doles out praise only where it is strictly owed — and, the poet implies, would owe him almost none. To 'hang more praise upon' someone is to add, as ornaments, tributes beyond what is warranted. OED records 'niggard' as an adjective meaning 'meanly sparing, grudging' from the fifteenth century.