Wa-wa

noun
1.
wah-wah.
adjective
1.
producing a muted, bawling sound like that of a trumpet with the hand moved momentarily over the bell:
a wah-wah effect on a synthesizer; a guitar with a wah-wah pedal.
noun
2.
a sound or effect like the muted sound of a trumpet, especially in music.
3.
an electronic device or attachment to produce such a sound, often used with an electric guitar.
noun
1.
the sound made by a trumpet, cornet, etc, when the bell is alternately covered and uncovered: much used in jazz
2.
an electronic attachment for an electric guitar, etc, that simulates this effect
wag one’s chin