What exactly is harkate?

I must sound really silly but when Anu Malik and Sonu sometimes say things like 'harkate bahut acchi thi', what do they mean by that.

(You guessed right, I am not a trained singer😕)

i dunno how to explain it to u without singing it---i'll try though....u knw when a singer kinda shakes his voice really quick-----have u heard teh song tera jaddoo chal gaya---in the antara there r lot of harkats if u hear carefully

itz like waves of the voice
shake the tune of it a lil..like going from high to low....low to high..
sumthing liek that....cant explain without singing

If you have heard the song "Is mod se jaate hain" (RD Burman), what Lata does in the word MOD, in the first line, is typically a harkat in classical music. Additionally, harkat is also the variations given to the same word/phrase when it repeats later in the song. (In the same song, listen out for the word MOD when it comes again, Lata gives a variation.)

Hope this helps