Could someone explain the meaning of the "to [put a] boot in the ass to do something" idiom? Cambridge Idioms Dictionary only mentions put the boot in as "to make a bad situation worse" and I'm not really sure if this is what I need.
Edit. More precisely, I'm thinking about such an example:
Does Google need a strong engineer to put boot in ass in developing the next XXX ...
The expression "a kick in the ass" (or, more mildly, "a kick in the pants") is sometimes used to refer to jumpstarting an individual, or getting a situation back on the right track, as in:
"Our son needs to get a job!"
"Yes, he needs a good kick in the pants."
It stands to reason, then, that "boot" can be substituted for "kick," since that's the net result, when the one doing the kicking happens to be wearing boots.
He himself felt sorry for the people who were in horrible pain, but some need the good boot in the ass. (J.E. Jackson, Camp Pain: Talking With Chronic Pain Patients, 1999).
If you want, check out this Ngram. You can see that all these phrases are used, but kick in the pants seems to be most common.
Your example usage:
Does Google need a strong engineer to put a boot in the ass to develop the next XXX ...
reads a little awkward, since it's usually an outsider, or one with some authority, doing the kicking, and it's hard to tell whose butt is going to be kicked in that sentence. (Google's?) If the "strong engineer" is in charge of a group of engineers who are developing XXX, then the expression might work, but I'd probably write more like this:
Google needs a strong engineer to put a boot in the ass of the team developing the next XXX ...
I'm not positive, but I think giving "a boot in the ass" is another way of saying that something or someone needs "a kick in the pants."
"a kick in the butt" also "a kick in the pants": forceful encouragement to do something
To increase in severity, you could add stiff, as in: "A stiff kick in the pants."
EDIT: This increase in severity stands out to me. My argument is that "a boot in the ass" is just a harsher way of saying "a kick in the pants" and, in the opposite direction, I think the phrase "rip a new asshole," as in "after your performance on the field yesterday, the coach is going to rip you a new asshole," is a harsher iteration still. An ngram search on all three terms: "kick in the pants", "boot in the ass", and "rip you a new asshole", finds that "a kick in the pants" became increasingly popular from 1925-1940 and then dropped off dramatically around 1944. This is about the same time that "a boot in the ass" registers in Google's records. It's not until 1979 that "rip you a new asshole" registers. "Kick in the pants" is still the most commonly used expression by a large amount--the other two are not "fit to print" by most standards--but it looks like we are finding harsher and harsher iterations.
Out of curiosity, I did the same search for the following three phrases that, arguably, increase in magnitude as well:
Give a damn.
Give a shit.
Give a fuck.
A similar pattern occurs.
Google registers hits for "don't give a damn" as far back as 1867; "give a shit" doesn't show up with any regularity until 1929; and "give a fuck" registers 12 years later in 1941. What's also interesting about this particular grouping is the sharp drop off "don't give a damn" follows, and, to a lesser extent, "don't give a shit", starting in 2002. "Don't give a fuck" is the only phrase seeing its numbers increase.
Maybe this is intuitive, maybe not. What I take away is that English speakers like to hone the edge of a dulled expression.
