"Pushbike". Probably the worst of the lot, this implies that (a) cycling is extremely hard and outdated compared to a motorbike and (b) you are supposed to lunge at the pedals like someone doing a gym leg press, not spin them smoothly. Only ever used by non-cyclists.
"Road bike". An unhelpful term which originated around the time of the MTB boom in the 1990s. It almost always means "road racing bike" but you never quite know if the speaker is referring to anything with smooth tyres.
"Crossbar". Doesn't cross anything, really. Almost always found on a "pushbike".
"10 speed" (or, for that matter, anything from "7 speed" upwards). Until the 1980s, bikes were described in terms of the total number of gear combinations, i.e. 5-speed meant 1 x 5, 10 speed meant 2 x 5 and 12 speed meant 2 x 6. Then that extra sprocket appeared and suddenly everyone forgot about the number of chainrings. OK when referring to a cassette, but my 9-speed touring bike actually has 27 combinations and a 9-speed racing bike probably has 18. To confuse matters further, a 1980s European-made road racer is almost always called a "ten speed" in the USA to this day, preserving the original convention.
"Dynamo". No, it's not. The Americans have this sorted, and call it a generator, neatly ducking the issue.
"Wheel" used to refer to a tyre.
"Suicide levers". A melodramatic term which I think originated from Richard's Bicycle Book, a truly depressing tome of bicycle myth and legend (read it and you'll probably never leave the house on two wheels again). They did have a lot of travel but in most cases they would never hit the bars (they swung up just in front of them) and they were better than nothing if you got caught on the hop while riding on the tops. It's worth remembering that brake levers of that era were also shite when applied from the hoods, until Shimano moved the pivot point in the late 1980s.
Any more?
