This week, the continuing war of words between Donald Trump and Ted Cruz turned to campaign ads and social media which included photographs of the candidates' wives. Donald Trump tweeted that Cruz should should "be careful" or he would "spill the beans" on his wife, Heidi Cruz.
In a statement to reporters, Ted Cruz said:
I don’t get angry often. But you mess with my wife, you mess with my kids, that’ll do it every time. Donald, you’re a sniveling coward. Leave Heidi the hell alone.
Snivel here means “to speak or act in a whining, sniffling, tearful, or weakly emotional manner.” It originally meant “to have a runny nose,” so it’s not surprising that it comes from sniffle and ultimately from sniff, words that developed by imitating the sound that they describe.