Borrowed from Latin intercurrens, equivalent to inter- +‎ current.

intercurrent (not comparable)

1. (obsolete) Running between or among, in a physical sense; interlayered.
   • 1659 December 30 (date written), Robert Boyle, New Experiments Physico-Mechanicall, Touching the Spring of the Air, and Its Effects[…], Oxford, Oxfordshire: […] H[enry] Hall, printer to the University, for Tho[mas] Robinson, published 1660, →OCLC:

     Intercurrent Ethereal Substance

2. Coming between, temporally; intervening in time.
   • 1661, John Fell, The Life of The most Learned, Reverend and Pious Dr H. Hammond:

     [B]esides the intercurrent offices of life, his reception of Visits, answering of Letters, his constant Preaching and Catechising, he found leisure to write his Tract of Fundamentals, his Paraenesis, his Review of the Annotations […].

   • 1913, Havelock Ellis, Love and Pain:

     As fatigue increases, the perception of the intercurrent excitation is retarded; an odor is perceived as exciting before it is perceived as a differentiated sensation […].

3. (medicine, of a disease or condition) Simultaneous; occurring at the same time as, or during the period of, another condition.
   • 1848, Robley Dunglison, The practice of medicine: a treatise on special pathology and therapeutics:

     In intercurrent pneumonia, or such as occurs in the course of another disease, the absence of the characteristic expectoration, according to M. Andral, is noticed.

   • 1921, Montagu Lomax, The Experiences of an Asylum Doctor, Allen & Unwin, page 97:

     As a matter of fact, these drugs are often used […] to save the doctors the trouble of making a diagnosis, or finding out the cause of some intercurrent malady.

4. (medicine, of a disease or condition) Not belonging to any particular season.

• intercurrently

• comorbid

intercurrent (plural intercurrents)

1. (rare, obsolete) Something intervening.

intercurrent

1. third-person plural future active indicative of intercurrō