tighties

Etymology 1
From.

Noun

 * 1)  Form-fitting.

Noun

 * 1)  Men's or boys'.

Usage notes
Tighties are said to come in pairs, which is to say that the phrase "pair(s) of" is used as a counter for them.

Synonyms

 * See Thesaurus:underwear
 * Y-fronts
 * jockeys
 * jocks
 * BVDs
 * bibidees
 * ginch
 * butt-huggers