1 “Adios, ___!” : AMIGO
6 Texter’s “you tell me” : IDK
9 Sweet braided bread : BABKA
14 Source of a pulse : SONAR
15 Modernizing prefix : NEO
16 Ingredient in a Whopper : ONION
17 Home of many champion marathoners : KENYA
18 “And just like THAT!” : BAM
19 Small contribution : ADDIN
20 Blowout victory, metaphorically : BLOODBATH
23 Chichén ___ (Mayan archaeological site) : ITZA
26 Latin “wolf” : LUPUS
27 Hulking brute : OGRE
31 Wild backdrop for “Wuthering Heights” : MOOR
32 Biblical patriarch who begat Methuselah : ENOCH
33 Lead-in to ever : WHOM
34 Device for taking notes? : ATM
35 Verbal facepalm : DOH
36 Message meaning “I can’t be reached right now” : OOO
37 “Welcome Back, Kotter” role of 1970s TV : GABE
39 Yusuf ___, adopted name of singer Cat Stevens : ISLAM
41 Subtle summons : PSST
42 Woman’s name that becomes another woman’s name when an “M” is added to the front : ELISSA
44 Missouri tributary : PLATTE
46 One part of a swimming pool : DEEPEND
48 Beat rapidly, as eggs : WHISKED
49 Center : CORE
50 Something of miner concern? : ORE
52 Commotion : STIR
53 A little cute? : ELFIN
54 Comedy bit : GAG
55 Broadway star LuPone : PATTI
57 Talent : GIFT
58 Big softy, perhaps : CRIER
60 Put through the self-checkout : SCAN
61 Research campus in upstate N.Y. : RPI
62 With 66-Across, spooky property that might include a 20-Across and a 7-, 25- and 28-Down : HAUNTED
64 Went underground : HID
65 Exit key : ESC
66 See 62-Across : MANSION
67 Country music’s ___ Young Band : ELI
68 Buttonless shirt : TEE
69 Carry-___ : ONS
70 Airport org. : TSA
71 Intelligence org. : NSA