longly

From long +‎ -ly.

longly (comparative more longly, superlative most longly)

1. For a long time; wearisomely.
2. (obsolete) With longing desire.
   • c. 1590–1592 (date written), William Shakespeare, “The Taming of the Shrew”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act I, scene i]:

     Master, you looked so longly on the maid,

• The usual adverb corresponding to several adjective senses of long is itself also long, not longly.