
1) Alejandro singer, casually 2) All atwitter 3) Ape over 4) Applause singer 5) Ardently fond 6) Artpop musician, casually 7) Baby talk 8) Bananas 9) Bitten by the love bug 10) Blithering 11) Blown away 12) Bonkers 13) Born This Way Lady 14) Born This Way singer 15) Bowled over 16) Carried away 17) Commitable
Found on
https://www.crosswordclues.com/clue/gaga

1) Doddering 2) Doddery 3) Enamored 4) Infatuated 5) In love 6) Loving 7) Old 8) Senile
Found on
https://www.crosswordclues.com/clue/gaga
[god] Gaga is a minor Babylonian deity featured in the Enûma Eliš. She is sent by Anshar to the forces of Tiamat with the formal announcement of Marduk`s readiness to battle Tiamat. ...
Found on
http://en.wikipedia.org/wiki/Gaga_(god)

Gaga is slang for senile, crazy or besotted.
Found on
http://www.probertencyclopaedia.com/browse/ZG.HTM
No exact match found.