To dig in

to cover by digging; as, to dig in manure.
To entrench oneself so as to give stronger resistance; - used of warfare or negotiating situations.

See also: Dig, Dig

Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.
References in periodicals archive ?
"You are never going to go a whole season playing well, you are going to go through times where you have got to dig in.
Plea: Micky begs cops to dig in hunt for Keith's grave Murdered: Keith, 12, was never found
We had to dig in and it's not always going to be silky football."
The level of investment made by a distributor also often exceeds that of a sales agent, making the distributor more likely to dig in its heels when facing a threat to end its franchise.