“Toppy” means that a stock (or the stock market) is at or near a “top,” so buying is risky and selling might be in order. “Toppy” can be a matter of opinion; one stock analyst can consider the market to be “toppy,” but another stock analyst might disagree and think that the stock market has room for more growth.
 
“Toppy” has been cited in print since at least 1878, when the word was used in a New York (NY) Herald story about the stock market.
 
 
Investopedia
What Does Toppy Mean?
A slang term used when markets are reaching highs that are unstable, and therefore a decline can be expected. In the U.S. the Dow Jones Industrial Average, the Nasdaq and the S&P500 are all used to gauge the overall market. The term “toppy” is used when these indexes are rising, but there is analyst sentiment indicating a potential decline.
 
(Oxford English Dictionary)
toppy, adj.
Stock Exchange. Of a market currency, etc.: high and unstable.
1961 Spectator 26 May 774   When markets became ‘toppy’ he should be busy switching from vulnerable to stronger positions.
1968 Economist 5 Oct. 81/2   What could be developing in London is a ‘toppy’ situation for a few months as the market consolidates the laurels it has earned.
1979 Daily Tel. 2 Aug. 17   Sterling suddenly looked toppy.
1983 Times 28 Apr. 16/2   If, however, the market looks ‘toppy’, it is the highest-rated sectors which are likely to suffer most.
 
13 July 1878, New York (NY) Herald, “The Stock Market Active and Weak,” pg. 8:
In the present “toppy” state of the market, however, the most whimsical rumors possess the authority of facts, and prices are as likely to take fright at a lamb as at a lion.
 
13 May 1881, New York (NY) Herald, “Stocks React in the Last Hour,” pg. 9:
Apart from the fact that values had grown “toppy” from having had too much of a boost there were many rumors afloat (more or less true) that proved prejudicial to estisting prices.
 
22 October 1885, Cleveland (OH) Plain Dealer, “Speculative News and Gossip,” pg. 7:
The market begins to look very toppy. It ought to have a big break.
 
22 March 1897, New York (NY) Times, “Chicago in Wall Street,” pg. 8:
Chicago, a week or more ago, began to show an inclination to take an interest in the New York stock market. One crowd of Chicago operators went into Omaha six or ten points below the high price it reached last Thursday. This Chicago interest succeeded to stocks that had been carried by New York traders who became convinced that Omaha looked “toppy” around 55 and 56, and they sold out while the market went on upward ten points more.
 
Google Books
December 1907, The Ticker, “Tips To Tickerites” by Rollo Tape, pg. 13:
I keep pushing the stop order up until the stock has a quick bulge or looks “toppy,” when I close out.
 
Google Books
March 1914, Moody’s Magazine, “Financial Forecasting” by James H. Brookmire,  pg. 144, col. 2:
The investor who is a business or professional man primarily, and a speculator only incidentally, should sell out when the market is still strong, but successively “toppy,” for the average trend during this period, which is all he should consider, is either stationary or only slightly upward.
 
Google Books
Practical Ways to Build a Fortune in the Stock Market
By David L. Markstein
New York, NY: Cornerstone Library
1969
Pg. 78:
A tendency of the gold average to rise when the whole market is becoming toppy nonetheless does exist, along with a tendency for the average to continue rising while the market is in the doldrums or going down and to drop just when things seem to be improving for the rest of the stocks.
Pg. 169:
As some inidividual stocks appeared “toppy” and were sold, the proceeds were therefore held in cash reserve waiting for a cheaper market.
     
OCLC WorldCat record
How High Is High? - By some measures, stocks look reasonably priced these days. Yet a unique gauge of the earnings cycle suggests the market is decidedly toppy.
Author: James W Paulsen
Publisher: Chicopee, Mass. [etc.]
Edition/Format:  Article : English
Publication: Barron’s national business and financial weekly. (October 09, 1995): 19
Database: ArticleFirst
   
Google Books
How to Retire Young and Rich
By Joseph S. Coyle
New York, NY: Warner Books
1996
Pg. ?:
This is generally a destructive impulse and is the basis for what market experts describe as the speculative froth that characterizes a “toppy” market—that is, one that has risen to its peak and is poised for a collapse.
 
Google Books
Short-Term Trading in the New Stock Market
By Toni Turner
New York, NY: St. Martin’s Griffin
2005
Pg. 9:
If a market looks “toppy” or “frothy,” and indicators signal that it’s overbought, we take profits.
 
OCLC WorldCat record
Cream of the Crop - COVER STORY: There are many paths to the top for women financial advisers. An exclusive ranking of 100 who made it, and where five see investment opportunities now. Hedging against a toppy stock market.
Author: Suzanne McGee
Publisher: Chicopee, Mass. : Dow Jones & Co., 1994-
Edition/Format:  Article : English
Publication: Barron’s. (June 11, 2007): 32
Database: ArticleFirst
     
The Market Financial
Best Setups For A Toppy Market
Written by Nicholas Santiago
Jan 26, 2011
The market has been on a one way path for months now, each sell off being negated by another move higher a day later.