Troll and trolling are slang terms used almost exclusively among gay men to characterize gay, bisexual and questioning or bi-curious men who cruise or "wander about looking" for sex or potential sex partners or experiences "in a notably wanton manner and with lessened standards of what one will accept in a partner." The term can be used positively or negatively depending on the speaker, usage and intent and can describe the person or the activity. Although often referring to "an unattractive older gay man" and although troll as a slur "is primarily a visual, not a behavioral" judgment, the phrases can be used for anyone who is trolling, regardless of the putative troll's age or perceived attractiveness.
Pejorative use
As a verb, "to troll" is not necessarily pejorative, with "trolling for sex" merely a synonym of cruising for sex.
The same is not true of "troll" as a noun describing a person, usually an elderly or unattractive gay male (a "troll") aggressively seeking younger partners ("twinks" or "chickens"). This usage carries all of the negative connotations associated with "dirty old man" outside the gay community; editorialists in the gay press also occasionally cite this usage as evidence that a gay community which values youth and physical attraction is marginalising its elderly.
Origin and historical usage
Troll as gay slang is amongst the lexicon of the cant Polari used in the gay subculture in Britain which has become more mainstream with transcontinental travel and online communication. There is still debate about how Polari originated but its origins can be traced back to at least the 19th century.
The term troll probably became equated with cruising because a troll is a "creature of Scandinavian folklore depicted as a devilish imp who lives in dark places and 'patrols' in an endless search." "The word trolla in Swedish means ‘to charm or bewitch’." Or perhaps from trolling as trolling for fish: Cast a wide net and hook whatever you can.
"As a Polari word, troll can mean ‘to walk effeminately’, or ‘to walk, seeking sex’." Trolling can be used almost interchangeably with cruising and like much of Polari usage was probably meant to disguise what was being talked about because being gay was (and in some contexts still is) taboo and discussing gay sex in any public area can be risky.
The word "troll" has remained unfamiliar even to many gay men in Britain, who have never heard, used, or needed to use the term. Regular customers in the same gay bar might have different takes on the usage – one simply referring to cruising, another referring to a negative version of a troll as a someone who "will have your skin crawling in seconds with his lascivious looks and raunchy repartee," another meaning older gays who prefer to troll for younger guys.
Variations on troll exist. A gay culture author asserts that trolley-dolly may be "derived perhaps from a combination of lalies and troll. A trolley-dolly (contemporary gay slang) is a gay flight attendant." Some say, however, that the phrase references the duty-free and drinks trolleys pushed by flight attendants; many people also use the phrase to refer to female flight attendants and in the UK it is often applied to supermarket checkout operators.
"Trolling" is also a term used for generations among fishermen in boats, to describe the way they let a line with a hook and bait on the "fishing line" follow along behind the boat moving slowly, hoping that this slow baiting of the fish will result in a catch. In Gay sub-cultural slang usage would often be coded to seem as though the speaker was talking about "fishing behavior'" but the "gay slang" usage decodes the message to mean "cruising for sex" and luring the potential contacts [catch]. The homosexual "cruising" could be called "trolling" to mean moving along slowly and letting potential contacts ["catches"] have opportunity to "take the bait" i.e. connect for sex. It does also carry the implicit meaning of being a behavior done by older less desirable men seeking sex in public places, but younger people may use the term either to describe serious sexual hunting, or to make light of it, and by using the term "trolling" to put a humorous light on what is considered to be a somewhat socially questionable behavior.