Infrequently.

1

1854.  He had, some years ago, in connection with his pastorate, a small congregation in the country, to which he preached semi-occasionally, at a private house.—Knick. Mag., xliii. 322–3 (March).

2

1854.  Jack Cathcart, a former college mate of Eliot’s and mine, who was, as his parents had every reason to believe by his letters, diligently employed in making himself a scientific physician and surgeon, but, in point of fact, walking the hospitals but semi-occasionally, and seeing life in Paris very constantly; especially that part of it which is to be seen by gas or lamplight.—Putnam’s Magazine, iii. 506/1 (May) (Bartlett).

3

a. 1854.  Semi-occasional intoxication.—Dow, Jun., ‘Patent Sermons,’ iii. 90.

4

1858.  Our mails [arrive] only semi-occasionally, or now and then.—Olympia (W.T.) Pioneer, Aug. 27.

5

1876.  The shelves being a foot deep, as many more books or pamphlets that are not to be discarded, but are only wanted semi-occasionally, can be ranged behind the other books and pamphlets.—Clarence Cook, ‘Beds and Tables, Stools and Candlesticks,’ Scribner’s Mag., xi. 488/2 (Feb.) (Bartlett).

6