Having had their fling with mannish styles for fall and winter, fashion's powers-that-be are realigning their sights. Next season will not be so overwhelmingly masculine. Spring, according to what was seen in the first of two weeks' advance showing on Seventh Avenue, is going to be different. Spring will be what the poets and songwriters always said it was supposed to be. Spring will be . . . romantic.
What is, or is not, romantic is naturally being given plenty of latitude. The big shirt - a leading theme repeated in New York as often as at the recent European openings - does not exactly call up a hearts-and-flowers image. Like the oversized trenchcoat, another style prevalent for spring in airy cottons or cires, the big shirt looks like a holdover from the androgynous dressing that has been the preoccupying trend lately.
Still, as presented by Danny Noble, the big shirt could conceivably qualify as romantic. The models at the show he and his wife, Annette, put on wore pale makeup and tousled peruke wigs, which reminded some of the audience of the Peter Shaffer film ''Amadeus'' and gave the Nobles' clothes an 18th-century air.
Slit down the back so the tails could be knotted in front, the Noble shirt has a tent-like cut but a small collar, worn open. It recurs in many forms in the lighthearted collection and combines beautifully with vests, loose blazers, and pants of ticking stripes and paisleys in black and white. Dress-length shirts in silk gauze come in vivid brights (peacock blue or orange, for instance). These sometimes button at both back and front. Candy-stripe shirtings and crinkled nylon (for a huge red trench) are some of the other fabrics.
Relatively new on the American fashion scene, the Nobles came here from London a few years ago and set up their work place in Philadelphia. Their clothes have the clean looks and insouciant appeal of the best of the new young British designers, and their talent has already been honored by a Coty award nomination.
If romantic is analogous to feminine, Mrs. H. Winter has been there all along. That women should dress like women is her guiding principle. It is illustrated by her well-cut raincoats of cloque cire, sometimes combined with canvas dropcloth, and by the willowy dresses of supple rayon jersey she is doing for spring. She uses shirring, a detail that is cropping up often these days, to frame necklines and in a drawstring effect at the side of short skirts.
Most of Harriet Winter's skirts do, however, tend to be longish. But length continues to be of little consequence to many designers. ''Hems,'' as Mrs. Winter puts it, ''are so unimportant today.''
Short should nevertheless be noted as a definite direction for next spring and summer. Getting in early on the trend, Bloomingdale's New York has been featuring a group of ''Short Subject'' dresses for night birds and other partygoers to wear now and on through the holidays. Customer reaction has been very positive. Stephen Sprouse, the new young designer whose minis with matching scribble-print tights are considered the fun look of the moment, is continuing in this 1960s vein with little knee-baring shifts in hot neon colors for next season. His followers wear them under long voluminous coats.
If not short skirts, then shorts that are loose and slightly flared. Adri shows them in printed cotton with easy tops and casual jackets as well as in silk with bulky knit sweaters.
Issey Miyake's ready-to-wear with the Plantation label was presented in the rectory auditorium of St. Bartholomew's Church. Tokyo's wonder-man concentrated on jump suits with deep armholes, drawstring pants with big shirts, and roomy smocks with large, low-placed patch pockets. The Momix dancers, acting as models , included a man on stilts who was wearing a jump suit so long it could be listed in the Guinness Book of Records. Mixtures of tone and texture, as in the linen and silk V-neck chemise of lichen green, are admirable and everything looks easy and summery.
The Mary McFadden collection is, so she says, inspired by China's first emperor, Qcinq Shi Huang. Designs adapted from the uniforms of his bodyguards are used in Ms. McFadden's brocades and hand-painted silks. What caught the eye at her showing, however, were the black-with-white finely pleated evening gowns, sumptuous in their simplicity and not particularly Chinese. Models wore the huge chandelier-type drop earrings that are the latest for gala nights.
Elsewhere on Seventh Avenue, dresses that outline the body with gathers about the hipline and other strategic points indicate that closer attention is due for the female form. Soft new colors - peach especially - are appearing among the hot brights and there is much talk of romantic makeups, romantic this, and romantic that. Whether the boy cut and cross-dressing of the gender-blending sort will survive is yet to be determined.