Unreimbursed employee business expenses used to be a miscellaneous itemized deduction subject to the 2% of adjusted gross income floor. However, this deduction has been suspended for 2018 through 2025, so no deduction is currently allowable.
A portion of earnings withheld by an employer or put into a retirement plan for distribution to the employee at a later date. If certain legal requirements are met, the deferred amount is not taxable until actually paid, for example, after retirement.