It is unlikely this word — meaning bask in the sun — will be part of your everyday vocabulary, or even be recognised, as it is unknown outside books about defunct words — I can find only a couple even of those that include it.
It derives from the Latin verb apricari, to bask in the sun or to sun oneself, which is related to apricus, of a sunny place. If it brings to mind that delicious distillation of raw sunlight, the apricot, that’s a false trail. However, it has been suggested that the fruit’s name may have been partly influenced by apricus during its journey from Latin praecox, early-ripening, to Greek, Arabic and Spanish and on to French and English.
Apricate first appeared in English around 1690 in an anecdote by the British antiquarian John Aubrey about Sir John Danvers: “His lordship was wont to recreate himself in this place, to apricate and contemplate, with his little dog with him.” Aubrey sent a copy of the manuscript to his friend John Ray, who replied in September 1691 that he wasn’t critic enough to censure another man’s writings but went on, “Some words I have noted, that do not sound well to my ears,” among which he included apricate as a new-coined word to be avoided. Although Aubrey’s text was published in 1697, the year of his death, with apricate in it, most people have since taken that advice. As long ago as 1847, James Halliwell-Phillipps included it in his Dictionary of Archaic and Provincial Words.
One of the few to use it, in a figurative sense, was James Russell Lowell, in a satirical piece that appeared in the Atlantic Monthly in February 1863. It purported to be a letter from that fount of Yankee pedantry, the Reverend Homer Wilbur, which was said to have been found on his desk after his death (Mr Wilbur was ostensibly the editor of The Biglow Papers, a humorous work by Lowell):
The infirm state of my bodily health would be a sufficient apology for not taking up the pen at this time, wholesome as I deem it for the mind to apricate in the shelter of epistolary confidence, were it not that a considerable, I might even say a large, number of individuals in this parish expect from their pastor some publick expression of sentiment at this crisis.