4 times

(1) James 3:11
Doth a fountain send forth at the same place sweet [water] and bitter?
τὸ γλυκύ [to gluku] accus. sing. neuter.

(2) James 3:12 
Can the fig tree, my brethren, bear olive berries? either a vine, figs? so [can] no fountain both yield salt water and fresh.
γλυκύ [gluku] accus. sing. neuter.

(3) Revelation 10:9 
And I went unto the angel, and said unto him, Give me the little book. And he said unto me, Take [it], and eat it up ; and it shall make thy belly bitter , but it shall be in thy mouth sweet as honey.
γλυκύ [gluku] nom. sing. neuter.

(4) Revelation 10:10 
And I took the little book out of the angel's hand, and ate it up ; and it was in my mouth sweet as honey: and as soon as I had eaten it, my belly was bitter.
γλυκύ [gluku] nom. sing. neuter.